In Thursday's 8-5 loss to the Chicago Cubs, starter Russ Ortiz went just 2 1-3 innings, forcing Houston manager Cecil Cooper to use five pitchers from the bullpen. With Doug Brocail and closer Jose Valverde on the disabled list, this has not been an ideal time for Astros relievers to pitch 30 2-3 out of the team's 54 1-3 innings in six games since May 2.

"They just need to go deeper into games," Cooper said of his starters.

The Astros (11-17) haven't had a starter get through six innings since April 28, spurring Cooper to add a 13th pitcher - Alberto Arias - to the roster on Wednesday.

"We know every guy in here that's a starter is going to go as long and hard as he can, for as many innings as they can," Ortiz said. "Right now we're in a little rough patch, but that doesn't mean that it's going to continue to happen. No starter likes to have to have the bullpen used that much."

Rodriguez (2-2, 2.19 ERA) has been leading Houston's staff, but he went a season-low five innings his last time out.

On Sunday, Rodriguez allowed three runs and six hits in a 7-5 win over Atlanta, but did not factor in the decision. The left-hander walked three, hit a batter and balked and wasn't as sharp as he previous three outings, when he gave up just two runs over 20 innings.

He'll look to bounce back with a stronger outing against a Padres team that has the majors' fourth-worst batting average (.240) and have plated the fifth-fewest runs (113).

In his last start against San Diego (13-16) on April 2, 2008, Rodriguez gave up four runs and eight hits in five innings of a 9-6 win, but wasn't a factor in the decision.

The Astros have dropped five of their last six at Minute Maid Park but have won four of their last five there against the Padres.

San Diego defeated Arizona 4-3 in 10 innings Thursday for just its fourth victory in 17 games.

David Eckstein singled in the winning run with one out in the 10th for the Padres' second extra-inning win in three games.

"It's really big for this club," Eckstein said. "Hopefully one day we'll win a game where it's not as close and as much pressure, but that seems like the only way we know how to win right now.

"This club has showed a lot of heart, especially in the tough times that we've been going through. We've just got to keep pushing forward."

Chad Gaudin (0-1, 5.06) takes the hill Friday looking to help the Padres win back-to-back games for the first time since winning three in a row April 16-18.

After throwing five shutout innings against Colorado in his first start of the season on April 28, Gaudin gave up six runs and eight hits in 5 2-3 innings of a 7-3 loss to the Los Angeles Dodgers on Sunday.

Gaudin, who signed with the Padres in April after being released by the Chicago Cubs, threw 3 2-3 scoreless innings of relief in two appearances against the Astros last season.