October, 1988 — Washington Post baseball writer Thomas Boswell claims Jose Canseco is "the most conspicuous example of a player who has made himself great with steroids." Canseco, coming off the first 40 home run-40 steal season in baseball history, denies using steroids before Game 1 of the ALCS at Fenway Park. The Athletics slugger wins the MVP award.

June 7, 1991 — Baseball commissioner Fay Vincent sends a memo to each team announcing that steroids have been added to the league's banned list. No testing plan is announced.

May 7, 1992 — Trainer Curtis Wenzlaff is arrested for steroids distribution. Wenzlaff later publicly admits helping Canseco and 20 to 30 other major leaguers obtain steroids, but refuses to discuss another former client, Mark McGwire.

July 15, 1995 — In an article by Los Angeles Times sports writer Bob Nightengale, Padres general manager Randy Smith is quoted as saying, "We all know there's steroid use, and it is definitely becoming more prevalent." Also in the article, Tony Gwynn states: "It's like the big secret we're not supposed to talk about."

Aug. 22, 1998 — A jar of androstenedione is discovered in the locker of Cardinals slugger Mark McGwire, who, along with Sammy Sosa, is chasing Roger Maris' single-season home run mark of 61. McGwire admits using the drug and goes on to hit a record 70 home runs. The precursor to steroids is not yet illegal in Major League Baseball.

April, 2001 — Baseball implements its first random drug-testing program in the minor leagues. All players not on a team's 40-man roster are subject to random testing for performance-enhancing drugs. The penalty for a first positive test is 15 games. Players testing positive five times will receive a lifetime ban.

Oct. 5, 2001 — Barry Bonds breaks McGwire's mark with his 71st home run off Chan Ho Park of the Dodgers. The 37-year-old, who has never hit 50 in a season before, goes on to hit 73.

May 28, 2002 — Ken Caminiti is quoted by Sports Illustrated as saying he used steroids during his MVP season in 1996 with the San Diego Padres, when he hit a career-high .326 with 40 home runs and 130 RBIs. He estimates half the players in the big leagues were using them.

Aug. 7, 2002 — Players and owners agree to their first joint drug program since 1985, calling for anonymous testing to begin in 2003. If more than five percent of the steroid tests are positive in 2003 or 2004, players would be randomly tested for a two-year period. Players won't be punished for testing positive.

Feb. 17, 2003 — Baltimore Orioles pitcher Steve Bechler collapses on the field during a workout in Florida and dies from heat exhaustion. The medical examiner finds ephedra in his system. The league places ephedra on the list of banned drugs at the minor league level.

Oct. 29, 2003 — Less than two weeks after the U.S. Anti-Doping Agency says several track athletes tested positive for tetrahydrogestrinone (THG), baseball places the drug on its testing list for 2004. The league is barred from retroactively retesting 2003 urine samples by its own agreement.

Nov. 13, 2003 — The league announces that of 1,438 anonymous tests in the 2003 season, between five and seven percent were positive, triggering the start of random testing with penalties in 2004. A first offense will lead to counseling and a second offense to a 15-day suspension.

December 2003 — Ten players, including Bonds of the Giants and Jason Giambi and Gary Sheffield of the Yankees, are called to testify in front of a grand jury investigating the Bay Area Laboratory Co-Operative (BALCO), founded by Victor Conte.

Feb. 12, 2004 — Bonds' personal trainer, Greg Anderson, Conte, BALCO vice president James Valente and track coach Remi Korchemny are charged in a 42-count federal indictment of running a steroid-distribution ring that provided performance-enhancing drugs to dozens of athletes.

April 12, 2004 — The Food and Drug Administration bans the sale of androstenedione, the steroid precursor used by Mark McGwire while setting the home run record in 1998. The FDA action automatically triggers a ban by baseball.

June, 2004 — The league begins testing major leaguers. Punishment for a first offense includes counseling, and names of offenders are to be kept anonymous.

Oct. 22, 2004 — President Bush signs the Anabolic Steroid Control Act of 2004 into law. The bill adds many steroid-based drugs such as androstenedione to the list of steroids classified as Schedule III controlled substances. All drugs banned by Congress are added to baseball's banned list.

Dec. 2, 2004 — The San Francisco Chronicle reports Giambi testified to a federal grand jury on Dec. 11, 2003, that he had used steroids for at least three seasons and had injected himself with human growth hormone in 2003.

Dec. 3, 2004 — The San Francisco Chronicle reports Bonds testified to a federal grand jury on Dec. 4, 2003, that he used a clear substance and a cream given to him by Anderson, but said he didn't know they were steroids.

Jan. 13, 2005 — Players and owners reach new drug-testing agreement calling for more banned substances and for a 10-day penalty for first-time offenders. Under the agreement, players failing drug tests will have their names released to the public.

Feb. 6, 2005 — The New York Daily News reports Canseco says in his book, "Juiced: Wild Times, Rampant 'Roids, Smash Hits, and How Baseball Got Big" that he injected McGwire with steroids and introduced several other sluggers to the drugs.

March 5, 2005 — Commissioner Bud Selig announces that between one and two percent of the 1,183 drug tests done in 2004 were positive for performance-enhancing drugs. Per the old agreement, no names are released because no player tested positive twice.

March 17, 2005 — At a hearing of the House Government Reform Committee, McGwire evades questions about steroid use as he testifies alongside Canseco, Sosa and Rafael Palmeiro, who denies having used steroids. Lawmakers scold commissioner Bud Selig and union leader Donald Fehr, saying baseball's penalties are too lenient. Some congressmen say legislation could be necessary.

April 3, 2005 — Tampa Bay outfielder Alex Sanchez becomes the first player suspended for steroids under the major league program.

April 4, 2005 — The league announces 38 minor leaguers tested positive for steroid use. By the end of the month, more than 50 minor leaguers have been suspended.

April 25, 2005 — Selig asks players to agree to a 50-game suspension for first-time steroid offenders, a 100-game ban for second offenders and a lifetime ban for a third violation.

July 15, 2005 — Conte and Anderson plead guilty to steroid distribution and money laundering, and Valente pleads guilty to one count of distributing illegal steroids.

Aug. 1, 2005 — Palmeiro is suspended for 10 days for testing positive for stanozolol, becoming the most prominent player to be penalized for steroids. Twelve players in all were suspended in 2005, each for 10 days.

Sept. 26, 2005 — Fehr counters Selig by proposing a 20-game suspension for first offense, a 75-game penalty for second and leaving the penalty for a third positive up to the commissioner.

Oct. 18, 2005 — BALCO's Conte is sentenced to four months in prison and four months' home confinement. Anderson receives three months in prison and three months in home confinement, and Valente gets probation.

Nov. 2, 2005 — Yankees outfielder Matt Lawton becomes the 12th and final player to be suspended 10 games after testing positive for a performance-enhancing drug. "I made a terrible and foolish mistake that I will regret for the rest of my life," he tells The Associated Press.

Nov. 15, 2005 — Players and owners agree, subject to ratification, to Selig's 50-game, 100-game, lifetime structure for penalties.

March 23, 2006 — Lance Williams and Mark Fainaru-Wada's book Game of Shadows is released. Citing BALCO transcripts and court documents, the book details a massive steroid conspiracy in the game of baseball.

March 30, 2006 — Conte is released from prison and insists he never gave performance-enhancing drugs to Bonds, says the book Game of Shadows is "full of outright lies."

April 13, 2006 — According to media reports, Bonds is under investigation by the U.S. government for perjury and tax evasion.

April 28, 2006 — Scientist Patrick Arnold pleads guilty to supplying BALCO with the performance-enhancing drug "the clear," the once-undetectable substance tetrahydrogestrinone that Bonds allegedly told a grand jury he'd unknowingly used.

June 7, 2006 — Federal IRS agents raid the home of relief pitcher Jason Grimsley, who admits using performance-enhancing drugs. According to a federal agent's affidavit, Grimsley gives up the names of players who also have used the drugs.

Oct. 1, 2006 — Roger Clemens, Andy Pettitte and Miguel Tejada are among the players that Grimsley accused of using performance-enhancing drugs, according to a federal agent's affidavit, the Los Angeles Times reports.

Nov. 1, 2006 — Mets relief pitcher Guillermo Mota is suspended 50 days for violating the league's drug policy, becoming the third and final suspended player of '06. Grimsley and Mets minor leaguer Yusaku Iriki are the others.

Dec. 27, 2006 — Federal appeals court rules the names and urine samples of about 100 Major League Baseball players who tested positive for performance-enhancing drugs in 2003 can be used by investigators.

April 26, 2007 — Former New York Mets clubhouse worker Kirk Radomski pleads guilty to selling performance-enhancing drugs to major leaguers. He cooperates with authorities, testifying before the same grand jury investigating Bonds.

Aug. 4, 2007 — Tigers shortstop Neifi Perez is suspended 80 games after testing positive a third time for stimulants. The harshest penalty handed out yet for drug use is not for a steroid, but the punishment is due to the league's crackdown on performance-enhancing drugs.

Oct. 31, 2007 — Outfielder Mike Cameron is suspended 25 games after testing positive a second time for a banned stimulant. "No steroids," Cameron tells a radio station. "I never took nothing like that before in my life. That would be 50 games, and that would affect me a whole lot more."

Nov. 1, 2007 — Bonds tells MSNBC he will boycott Cooperstown if the Hall of Fame displayed his record-breaking home run ball with an asterisk. "There's no such thing as an asterisk in baseball," Bonds said.

Nov. 15, 2007 — Bonds is indicted on five felony counts of perjury and obstruction of justice for allegedly lying when he testified he never knowingly used performance-enhancing drugs. If convicted, legal experts say Bonds could spend up to 2› years in prison.

Nov. 27, 2007 — Relief pitcher Dan Serafini becomes the second player suspended in '07 specifically for performance-enhancing drug use. Tampa Bay pitcher Juan Salas was the first.

Dec. 6, 2007 — Outfielders Jose Guillen and Jay Gibbons, linked in media reports to receiving human growth hormone, are suspended for the first 15 days of the 2008 season.

Dec. 7, 2007 — Bonds pleads not guilty to four counts of perjury and one of obstruction of justice.

Dec. 10, 2007 — The players' association files a grievance to overturn Guillen's 15-day suspension.

Dec. 13, 2007 — Former Sen. George Mitchell releases 409-page report on performance-enhancing drugs in baseball that implicates seven MVPs and 31 All-Stars — one for every position. It identifies 85 players to differing degrees, a list of baseball's elite that includes Clemens, Sheffield, Giambi, Eric Gagne and Troy Glaus.

Jan. 6, 2008 — Clemens files a defamation suit against former personal trainer Brian McNamee in Texas state court and denies using performance-enhancing drugs in an interview with CBS' "60 Minutes." McNamee told Mitchell he injected Clemens with steroids and HGH about 16-to-21 times during 1998, 2000 and 2001.

Jan. 7, 2008 — Clemens airs 17-minute taped phone conversation with McNamee, when his former personal trainer repeatedly asks, "What do you want me to do?" During a news conference, the seven-time Cy Young Award winner vows to tell the truth when he testifies in front of the House Committee on Oversight and Government Reform.

Jan. 9, 2008 — The House hearing involving Clemens, McNamee and Pettitte is postponed from Jan. 16 until Feb. 13.

Jan. 15, 2008 — Mitchell, Selig and Fehr appear before Congress. Before testimony starts, House Oversight and Government Reform Committee leaders announce they've asked the Justice Department to look into whether Tejada lied to committee staffers when questioned in connection to Palmeiro's perjury case in 2005.

Jan. 28, 2008 — Former Yankees second baseman Chuck Knoblauch agrees to talk to a House committee investigating drug use in baseball after initially failing to respond to an invitation to testify.

Feb. 8, 2008 — Former New York Mets clubhouse attendant Kirk Radomski is sentenced to five years' probation after cooperating with baseball's investigation into the use of performance-enhancing drugs.

Feb. 11, 2008 — Pettitte, Knoblauch and Radomski are taken off the witness list for a House hearing featuring Clemens and McNamee.

Feb. 13, 2008 — Clemens and McNamee testify before House committee, and neither wavers from their previous statements. McNamee says he injected Clemens with steroids and human growth hormone while the pitcher denies it, saying "I have strong disagreements with what this man says about me."

Feb. 16, 2008 — Addressing his inclusion in the Mitchell Report for the first time, Nationals catcher Paul Lo Duca acknowledged what he called "a mistake." The four-time All-Star was among the more prominent players cited in Mitchell's report on drug use in baseball. When a reporter asked what he was apologizing for, Lo Duca replied, "Come on, bro'. Next question."

Feb. 18, 2008 — Pettitte reports to spring training with the New York Yankees, and apologizes for using human growth hormone. Gagne, also identified as a user of HGH in the Mitchell Report, apologizes to his new Milwaukee Brewers teammates for "a distraction that shouldn't be taking place."

Feb. 27, 2008 — Congress asks Justice Department to determine whether Clemens lied under oath in testimony to a House committee.

March 21, 2008 — The perjury case against Bonds is put on hold for three months, with prosecutors telling a federal judge they plan to obtain a new indictment against baseball's home run king.

April 11, 2008 — Baseball players and owners strengthen drug rules again in response to outside criticism, agreeing to more frequent testing and increased — but not total — authority for the program's outside administrator. All players implicated in the Mitchell Report are given amnesty as part of the agreement. The deal also eliminates 15-day suspensions assessed against Guillen and Gibbons.

May 13, 2008 — Bonds is charged in a new indictment with 15 felony counts alleging he lied to a grand jury when he denied knowingly using performance-enhancing drugs and that he hampered the federal government's doping investigation.

June 6, 2008 — Bonds pleads not guilty when he is re-arraigned on 15 felony counts of lying under oath and obstruction of justice.

Nov. 24, 2008 — Three charges against Bonds are dismissed by a federal judge who leaves intact most of the indictment alleging he lied to a grand jury when he denied knowingly taking performance-enhancing drugs.

Dec. 4, 2008 — Federal prosecutors drop four counts of lying to a grand jury against Bonds, leaving him to face trial on 10 counts of making false statements plus an additional obstruction of justice charge.

Jan. 12, 2009 — Two people who were briefed on the matter confirm to The Associated Press that a federal grand jury is being asked to determine whether Clemens should be indicted on charges of lying under oath. Both speak on condition of anonymity because grand jury proceedings are supposed to be secret.

Feb. 7, 2009 — Sports Illustrated reports New York Yankees star Alex Rodriguez tested positive for two anabolic steroids during his MVP season with Texas in 2003.

Feb. 9, 2009 — Rodriguez tells ESPN he used banned substances while playing with the Texas Rangers from 2001-03 to justify his 10-year, $252 million contract.

Feb. 10, 2009 — Tejada is charged with lying to Congress about an ex-teammate's use of steroids.

Feb. 11, 2009 — Tejada becomes the first high-profile player convicted of a crime stemming from baseball's steroids era, pleading guilty in federal court to misleading Congress about the use of performance-enhancing drugs. Tejada also acknowledged he bought HGH while playing for the A's, but said he threw the drugs away without using them.

Feb. 12, 2009 — A federal judge dismisses most of Clemens' defamation lawsuit against McNamee, saying statements made in the Mitchell Report on doping in baseball are protected.

Commissioner Bud Selig says Alex Rodriguez "shamed the game."

Feb. 17, 2009 — Rodriguez holds a press conference when he arrives at spring training with Yankees. Making his second public attempt to explain a 2003 positive drug test, baseball's highest-paid player describes a clumsy scheme in which a cousin persuades him to use "boli" — a substance he said the cousin obtained without a prescription and without consulting doctors or trainers.

Feb. 27, 2009 — Bonds' trial is delayed indefinitely after federal prosecutors notify the judge overseeing the case that they will appeal her decision to exclude key evidence from the jury.

March 1, 2009 — Rodriguez meets with officials from baseball's Department of Investigations and Labor Relations Department for two hours. The commissioner's office releases a statement saying Rodriguez was "cooperative."

March 26, 2009 — Tejada is sentenced to one year of probation for misleading Congress.

May 4, 2009 — "A-Rod: The Many Lives of Alex Rodriguez" hits bookstores. Journalist Selena Roberts makes the case that Rodriguez likely used steroids in high school and may have taken HGH while with the Yankees in the biography of the MVP.

May 7, 2009 — Manny Ramirez is suspended for 50 games by Major League Baseball, becoming the latest high-profile player ensnared in the sport's drug scandals. The Los Angeles Dodgers star says he did not take steroids and was given medication by a doctor that contained a banned substance.