WASHINGTON -- The Rangers just couldn't get Milton Bradley into the lineup during their three-game series with the Nationals this weekend.

Bradley, who is third in the American League in hitting with a .332 average, was out of the lineup on Sunday for the fifth straight game with a strained left quadriceps muscle. The Rangers are off on Monday before they open a three-game series with the Astros in Houston on Tuesday.

"Hopefully, we'll have him available when we get to Houston," Rangers manager Ron Washington said. "We just have to wait on him. We never expected it to last this long. But you can't push somebody out there if they're not able to perform. If a guy says he can't go, you can't push him."

Bradley has been able to pinch-hit, and he was 1-for-2 with a single in the first two games of the series. If he does start in Houston, it will have to be in the outfield, because the designated hitter is not used at National League parks. That's worth watching.

Bradley, who had major knee surgery at the end of last season, is still working toward getting back to full strength and has had a couple of minor leg issues this season. His latest problem occurred after he had made seven of 11 starts in the outfield. Prior to that, he had made 22 of 23 starts at designated hitter. Washington said he doesn't believe the injury was related to using Bradley more in the outfield.

"When he's healthy, he can go out there," Washington said. "I don't think we're overusing him. Sometimes things just happen. I don't think putting him in the outfield has anything to do with it. We've been very conscientious on how we put him out there. I think our rotation is fine."

Washington said that Bradley needs to be able to play the outfield, at least on occasion, to maintain his high level of energy. A small sample of numbers backs that theory. Bradley has played 15 games in the outfield and is hitting .368 with six home runs and 18 RBI in 57 games. In 47 games at a designated hitter, Bradley is hitting .317 with nine home runs and 30 RBIs in 161 at-bats.

"Right now, we're playing the National League, so the only way to get him out there is the outfield," Washington said. "When we get back to the American League, we'll still spot him out there. He's got to have his release and feel he's contributing. Otherwise, if he's not having a good time offensively, he can bash up some bats.

"I'm going to get him time out there. I've got to. We'll play him out there when we feel like he can contribute. We'll just make sure we monitor his health and not overexpose him."