He allowed three runs on seven hits in his last start on July 6 against the Reds. Through six innings, Wells had given up just a solo homer, but then Ryan Hanigan hit a two-run homer that barely cleared the left-field fence in the seventh.
"For the most part, they barreled a couple balls, but by and large they hit [two] home runs off me and were within five feet of still being in the field of play, so that's kind of unfortunate, but it happens," Wells said.
Against the Astros in his first start of 2012, Wells went five innings, giving up five runs (two earned) on seven hits. He threw 100 pitches in the Padres' 5-3 loss.
Wells will be facing a much different lineup than he faced in June. Shortstop Jed Lowrie (knee, ankle) and catcher Jason Castro (knee) were placed on the 15-day disabled list before Sunday's game against the Giants. With Carlos Lee no longer on the team, the Astros will have at least a couple new faces in the batter's box against Wells.
Catcher Carlos Corporan and shortstop Marwin Gonzalez were added to the Astros' roster on Sunday and started. Gonzalez went 2-for-4 with a run scored and Corporan went 0-for-2 with a strikeout.
Lowrie sustained his injuries in the third inning of Saturday's game when Gregor Blanco slid into his right foot at second base. His right ankle is sprained and the peroneal nerve in his right leg is also injured. He headed back to Houston on Sunday for further evaluation.
Castro has an effusion (fluid) in his right knee. He started feeling discomfort in the knee on July 7 and hasn't played in a game since. His stint on the disabled list is retroactive to July 8. He had a .306 batting average in 24 games since May 31.
Padres: Amarista will continue to play all over
The only positions Alexi Amarista hasn't played for the Padres so far are first base, catcher and pitcher. He may not play those this season, but manager Bud Black said he will continue to play everywhere else.
"I think with Alexi, that's a great advantage for us ... his versatility and us feeling comfortable with him anywhere in the diamond," Black said. "We've got trust in him as an outfielder, trust in him as an infielder. He gives us maneuverability every day to do things, whether it's a double-switch or pinch-hit and stay in the game."
Amarista has played 28 games at second base, six at shortstop, six in left field, one in right field, one at third base and one in center field. He has yet to make an error.
Astros: Happ looking to bounce back
Left-hander J.A. Happ had a rough outing last time out, giving up seven earned runs in 6 1/3 innings against the Brewers, who hit three homers. Two came from Norichika Aoki and Ryan Braun in the first inning.
In the three starts before his last start, Happ had a 2.84 ERA in 19 innings and a 2-1 record. Happ has earned a decision in each of his last 13 starts: five wins, eight losses.
He has five career appearances against the Padres, owning a 2.74 ERA in 23 innings.
Reliever Wilton Lopez, out a month with a right elbow strain, returned on Saturday and pitched two scoreless innings in the Astros' 12-inning loss to the Giants. He threw 29 pitches in the outing and was not available to pitch on Sunday.
"It was outstanding to see him come back and throw the ball like he did," manager Brad Mills said Sunday. "That was definitely a bright spot."
According to Elias Sports Bureau, Everth Cabrera's steal of home in the Padres' 7-6 victory over the Dodgers on Saturday marked the first time in nearly 30 years that a Major League team won a regular-season game in which either the tying or go-ahead run was scored by a steal of home in the ninth inning or later.
The Astros have lost 13 straight road games, one shy of the franchise record. They are 9-35 on the road in 2012.