CHICAGO — Cubs ace Carlos Zambrano has right rotator cuff tendinitis and inflammation, an MRI confirmed today, a blow to Chicago's chances of winning the World Series for the first time in a century.

Zambrano received a shot of anti-inflammatory medication and hopes to return to the rotation next week.

General manager Jim Hendry said Zambrano is to start throwing again when the team begins a series in St. Louis on Sept. 10. If all goes well, Zambrano would start at Houston in the following series.

Zambrano, 13-5 this year, left his start Tuesday night against the Astros after five innings, saying he did not feel well. He was examined Wednesday by team orthopedist Dr. Stephen Gryzlo.

Zambrano is 1-1 over his last six starts and has made it past the fifth inning only twice.