© 2013 MLB Advanced Media, L.P. All rights reserved.

8/9/2013 11:27 P.M. ET

Berkman to begin rehab assignment on Saturday

HOUSTON -- Rangers designated hitter Lance Berkman, who has been on the disabled list since July 7, will begin a rehab assignment with Triple-A Round Rock on Saturday. Berkman is not to the point where he is 100 percent or even close to it.

But Berkman is to the point where he wants to find out if he can play or if it is time to walk away from the game. The only way to find out is on a rehab assignment.

"I'm still not sure if I could be a good enough player to go out and help this team," Berkman 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, who has been taking batting practice regularly, is sidelined with inflammation in his left hip and back. He is also dealing with a chronic sore right knee. As a switch-hitter, Berkman feels the inflammation when he swings from the right side, while the knee has impaired his ability to swing from the left side.

Berkman was hitting .254 with six home runs and 34 RBIs in 68 games and 244 at-bats before he went on the disabled list. He had a .355 on-base percentage and a .377 slugging percentage.

"I will be able to play; how effective I am remains to be seen," Berkman said. "That part is what's up in the air. I'm not sure what level I will play at. I wasn't happy with the level I was out before I got hurt. I don't think this is going to help."

Murphy not worried about future with Rangers

HOUSTON -- Rangers outfielders David Murphy and Nelson Cruz are both free agents after the season. The acquisition of outfielder Alex Rios -- who is signed through 2014 -- means the Rangers will likely be interested in re-signing only one of those two players.

Cruz is currently serving a 50-game suspension and, like Rios, he is also a right fielder. Since Murphy is a left fielder, the acquisition of Rios might give Murphy an edge in one regard as to whom the Rangers re-sign. But Cruz was having the much better season before he was suspended.

"I really don't know," Murphy said. "There's no reason to think about that right now. All I'm thinking about is winning. There are so many variables about me being a free agent after the season. I would drive myself crazy thinking about that. There's no reason to. Right now I'm playing for 2013."

Murphy went into Friday's game with the Astros hitting .224 with a .284 on-base percentage and a .383 slugging percentage. In 109 games, he has 12 home runs and 36 RBIs. That could suggest he has already been driving himself crazy thinking about free agency. He said that is not the case.

"I think it's easy to think that because the season hasn't gone the way I planned or other people planned," Murphy said. "But if there is one thing that's causing me not to have a good season at this point is losing my identity early in the season.

"Seeing the offensive players that left here, I thought I needed to hit with more power and drive in runs instead of me being me ... hitting singles, looking for singles, driving out of the ballpark once in a while, hitting doubles. I was expecting too much out of myself and trying to do too much."

Pierzynski, Frasor happy to be reunited with Rios

HOUSTON -- Rangers general manager Jon Daniels talked with catcher A.J. Pierzynski before acquiring Alex Rios from the White Sox. Pierzynski gave a strong endorsement, having been teammates with Rios for parts of four seasons before signing with the Rangers in the offseason.

"I love Alex," Pierzynski said. "I've always had a great relationship [with him]. He's a fun guy to have around and obviously very talented. He can do a number of things. Hopefully coming in here will invigorate him and give him a shot of energy.

"He's legitimate, one of those five-tool guys when he's right. I've seen Alex when he's at his best and when he's at his worst, and when he's right, there are not a lot of people better than him."

The Rangers acquired Rios from the White Sox on Friday for a player to be named later. Infielder Leury Garcia is expected to be that player, but he must first either get through waivers or be claimed by the White Sox. Rios also played for the Blue Jays in 2004-09, when he was a teammate with Rangers reliever Jason Frasor.

"He does everything well," Frasor said. "He plays good defense, he's a good hitter, obviously. He's a good player having a great year. If he keeps doing what he has been doing, he'll help us."

Rios is third among active players in most games played in the Majors without having played in postseason.

"I'm kind of happy for him," White Sox first baseman Paul Konerko said. "It's going to be a good shot in the arm for him. It wouldn't surprise me if he goes there and gets real hot."

"More than anything, Alex wasn't just a teammate. He was a part of our family," White Sox infielder Alexei Ramirez said. "For me personally, I learned a lot from him. It's really hard for me to see him leave."

Harrison exits rehab start due to hand numbness

HOUSTON -- Rangers pitcher Matt Harrison had to leave his rehab start for Triple-A Round Rock on Friday in the top of the fourth inning because of numbness in his left hand.

Harrison was making his third rehab start and came out after throwing just three pitches in the inning. He threw 60 pitches in all, allowing four runs on three hits and two walks. He did not strike out a batter.

"I felt strong from the get-go," Harrison said. "The ball was coming out of my hand good. Except for having to come out of the game as a precaution, a little bit of tingling, other than that, I just had some long innings, deep pitch counts. I threw a lot of pitches in those three innings."

Harrison, who underwent two back surgeries on April 23 and May 1 to repair a herniated disk in his lower back, will likely be sent back to Arlington to be examined by Dr. Keith Meister. Harrison missed much of the 2009 season because of surgery for thoracic outlet syndrome. That's a condition where a rib bone presses against a nerve and can cause numbness in a person's hand.

The Rangers were hoping Harrison could be an option for their rotation by the beginning of September. He was scheduled to make two more starts after this one.

Butler gets first start with lefty on hill for Astros

HOUSTON -- Outfielder Joey Butler, who was called up from Triple-A Round Rock on Monday, was in the lineup for the first time on Friday night with left-hander Erik Bedard on the mound for the Astros.

Butler was hitting .321 off left-handers at Triple-A before being called up. Butler grew up on the Mississippi Gulf Coast, and his family was coming to the game on Friday night.

"I'm very excited," Butler said. "It means a lot ... my first start, pretty exciting."

Butler made his Major League debut on Wednesday night when he pinch-hit in the ninth inning against Angels left-hander Nick Maronde. He lined out to second base.

The Rangers have to make a roster move on Saturday to make room for Alex Rios and will likely send either Butler or Engel Beltre back to Round Rock. Butler may be the one staying since he hits right-handed. Rios will play every day in right field, so Butler may end up playing left field instead of David Murphy when there are left-handers on the mound.

"He'll play tonight and then we'll make a decision tomorrow," Rangers manager Ron Washington said.

Worth noting

• Washington, on Daniels and the front office acquiring Rios and pitcher Matt Garza: "They did an excellent job. We felt we needed another pitcher and they went out and got us a pitcher. We certainly discussed before the Trade Deadline we'd like to have another bat and what he does is go out and get a bat. Not only a bat, but this guy is a complete player.

"You can't put into words how much we appreciate it. I'm very impressed with what Jon has done in getting Garza and Rios. Now it's up to us to finish it off."

• Reliever Matt West, who had Tommy John surgery on Aug. 22, 2012, and is still on the 40-man roster, is throwing the ball well on a throwing program in Arizona. Farm director Tim Purpura said he could be the latest success story for pitching rehab coordinator Keith Comstock.

• Nefatli Feliz allowed a hit and two walks over two-thirds of an inning in his first rehab assignment for Round Rock on Thursday. He'll pitch one inning on Saturday, take two days off, and pitch two innings on Tuesday.

T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, and follow him on Twitter @Sullivan_Ranger. This story was not subject to the approval of Major League Baseball or its clubs.