HOUSTON — The homestand had to end sometime. Not coincidentally, so did the Giants’ winning ways.

They changed back into their road grays Monday night and again failed to carry over momentum from a rollicking week at AT&T Park. Matt Cain (12-3) was beaten by two pitches, one of which wasn’t a glaring mistake, and Bengie Molina didn’t do much cleaning up as the Giants lost 4-3 to the Houston Astros at Minute Maid Park.
The Giants were on the verge of a little last-minute magic when Pablo Sandoval hit a two-out double in the ninth off closer Jose Valverde that scored Eugenio Velez. But Molina grounded out and the Giants fell to 21-32 away from China Basin.
They can’t alter their uniforms. But they might alter their cleanup hitter.
Giants Manager Bruce Bochy said he and General Manager Brian Sabean discussed the lineup before Monday’s game, and moving Molina out of the No. 4 spot was among the possibilities.
It’s clear that Molina, a free agent at season’s end, is a different hitter in the clutch this year. In 2007, his first year with the club, he posted a .338 average with two out and runners in scoring position. The following season, after the club parted ways with Barry Bonds, Molina became Bochy’s choice to hit fourth and the catcher justified the decision by hitting .318 in those clutch scenarios.
But after his game-ending groundout Monday, Molina’s average is down to .155 in 58 at-bats with two out and runners in scoring position.
He politely declined comment after the game.
“No, no, we’ll do what we think is best for the team,” said Bochy, asked if he had to weigh Molina’s pride and stature in the clubhouse. “We’re not concerned for feelings. We’ve got to do what’s right. He’s one of the best clutch hitters, I think, in this game. Whether we keep him there or move him, he’ll get it going. He can hit.”
The stat-inclined segments of the fan base would be quick to point out that Molina’s .268 on-base percentage is the worst among all major league starting players; his 3.08 pitches per plate appearance also is the lowest in the majors.
Those numbers are especially alarming for a cleanup hitter — the guy a major league lineup usually relies upon to be an on-base machine and make opposing pitchers sweat.
“He’s not locked in right now,” Bochy said. “That’s obvious. We need to get him going. But (Monday), we had good opportunities with everyone up there.”
They had seven hits in the first three innings against Mike Hampton but plated only two runs. Molina extended one rally with a single and Ryan Garko followed with another to drive in his first run as a Giant. Molina hit a sacrifice fly in the third inning — just his third RBI since the All-Star break.
After that, an aggressive lineup got a little too passive. Aaron Rowand and Edgar Renteria took third strikes to strand two runners in the third. The Giants loaded the bases in the sixth, but Cain took a third strike and plate umpire Eric Cooper rang up Eugenio Velez on a curveball.
Cain benefited from the strike zone, too. He didn’t walk a batter and threw 82 of 115 pitches for strikes. But with the Giants ahead 2-0, Geoff Blum dug out a curveball for a solo home run in the fifth inning. In the sixth, Kazuo Matsui hit a two-run homer that struck the mesh screen inside the right-field pole.
Cain said the pitch to Blum was in the location he wanted. He wasn’t sure if the 3-2 pitch to Matsui hit the inside edge.
“I guess he got the head to it,” Cain said.
Cain tied Tim Lincecum for the N.L. lead with four complete games. He has eight in his career, and before Monday night, he hadn’t lost while going the distance.