HOUSTON — David Murphy isn’t too worried about how the acquisition of Alex Rios affects his future with the Texas Rangers.Rios is signed through 2014 with a team option for 2015, and fills one of the Rangers’ needs for a corner outfielder in ’14 with Murphy and Nelson Cruz set to the free-agent market after this season.Murphy is well aware of that, but insisted it hasn’t weighed on his mind.“All I’m thinking about is winning,” Murphy said. “There’s a chance that it could cut into my at-bats, there’s a chance that it could affect my future with this team, but I’m playing for 2013.“We got a great thing going here and if we finish out the season the way we’ve been playing, we’ve got a great chance to do what we tried to get done in 2010 and 2011.”Murphy said he would drive himself crazy if he worried about his upcoming free agency with all the unknown variables tied to it.He hasn’t had the type of contract season that most desire, either. He has been relegated to a platoon role in left field, batting .224 with 12 home runs and 36 RBIs over 109 games.His second half is going better than his first half, though, and he admitted that he tried to do too much early in the year. He felt he had to show more power this season with the loss of players such as Josh Hamilton and Mike Napoli.“I may have lost my identity early on this season,” Murphy said. “Instead of just being me, going up there looking for singles, maybe driving a ball out of the ballpark every now and then, I was expecting too much of myself.“But I feel like myself now. I feel like I’m driving the ball with more consistency.”Rehab for BerkmanLance Berkman will begin a medical rehabilitation assignment Saturday for Triple A Round Rock.The 37-year-old slugger has been on the disabled list for more than a month with left hip inflammation and is still not 100 percent, but said it’s time for him to see if he can be a productive bat in the lineup.“I’m still not sure if I could be a good enough player to go out and help this team,” he said. “It’s still up in the air, but it’s about time to get to the point to see if I can. It’s not going to get much better sitting around on the disabled list.”Berkman went through running drills and batting practice Friday, and also had Astros team physician David Lintner go through a routine examination of his surgically repaired right knee.The Rangers are hoping Berkman can return to the form he showed early in the season when he batted .319 in April, rather than the .176 average he posted in his past 20 games before landing on the DL.“We’re staying in the process with him and maybe he can work his way out and we’ll see where it goes,” manager Ron Washington said.Harrison exitsLeft-hander Matt Harrison threw three pitches to start the fourth inning of a rehab start at Triple A Round Rock on Friday, but was pulled with numbness in his left hand as a precaution.He will be further examined and most likely sent to see Rangers physician Keith Meister in Arlington.Harrison went three-plus innings, allowing four runs (three earned) on three hits with two walks and no strikeouts over a 60-pitch outing. It was his third rehab start as he comes back from two early-season back surgeries.Harrison made two starts with Double A Frisco, allowing one run over five total innings.Briefly• Joey Butler made his first big-league start Friday, and doubled down the right-field line to start the third inning for his first big-league hit.• Saturday night’s starter, Derek Holland, is making his first start of the season against the Astros. He’s 7-1 with a 2.61 ERA in 12 road starts this season.• With three stolen bases Wednesday, Elvis Andrus reached the 30-mark for the season. It’s the fourth time he’s had 30 or more steals in a season, the most in franchise history.
Drew Davison, 817-390-7760 Twitter: @drewdavison