ARLINGTON, Texas -- Left-hander Martin Perez will pitch Friday in Seattle and take over the fifth spot in the Texas Rangers' rotation, manager Ron Washington announced after Sunday's 2-1 win over the Seattle Mariners.

If the rotation schedule holds, Perez would pitch twice against second-place Oakland down the stretch. The Rangers are three games up on the A's with seven games of the final 10 games of the season against them.

Perez takes over for Scott Feldman, who lasted just 2 2/3 innings in Saturday's loss, allowing six runs on seven hits. Feldman, who will go back to the bullpen, has lost his last five decisions and Perez has pitched well in two recent long-relief outings. That includes Saturday, when he relieved Feldman and pitched 4 1/3 scoreless innings with no hits, five strikeouts and one walk.

"He's been very aggressive, he's been keeping the ball down and he's been showing tremendous improvement," Washington said of Perez. "He's a very good competitor. We're going to give him an opportunity to take a few starts the rest of the way."

Perez said he's thankful for the chance and just wants to pitch and help the club win games.

"I just want to prepare myself well in the bullpen for the start," Perez said through an interpreter.

Perez said he feels more ready now than he did when he was first called up because he's learned "to just make his pitches and not think too much."

"I've been feeling good," Perez said. "When they've given me chances the last few times it's given me confidence."

Perez allowed two runs (both on solo homers) to the Tampa Bay Rays in five innings of relief last Sunday to go along with his 4 1/3 scoreless innings on Saturday vs. Seattle.