HOUSTON -- Unsatisfied with their production at first base and unsure when Hank Blalock will return, the Rangers are calling up first baseman Chris Davis from Triple-A Oklahoma.

Davis, a left-handed hitter with exceptional power, will join the Rangers on Thursday night at Minute Maid Park.

"We've been patient up to this point expecting Hank to be back for the Houston series," Rangers general manager Jon Daniels said. "Unfortunately, through no fault of his own, he had his latest setback. I don't expect it to be long-term and we expect to send him on a rehab assignment in the near future. But we felt this was an opportunity to give Chris a chance to see what he can do and see if we can't get more production out of that position."

Blalock has been on the disabled list since April 26. He was supposed to be activated on Tuesday but jammed his right hand in a rehab game with Oklahoma on Sunday, and the Rangers are unsure when he'll be ready to return.

The Rangers expect him back before the All-Star break, but right now he still has swelling in the hand and is unable to grip a bat. The Rangers are still planning on Blalock moving to first base when he comes off the disabled list, but right now Davis is their man.

"More than likely, I would expect Hank to play at that point," Daniels said. "We've had discussions about Chris some time ago, but we hoped Hank would be back by now. Rather than continuing to wait, this is a chance to look at Chris. I said before the season that the key to our season would be the health of our veterans and the continued development of our young players.

"The health has been a mixed bag. But one of the bright spots of the year has been the young players not only graduating to the big league level, but contributing to winning. Chris has a chance to be the next one."

Davis, the Rangers' fifth-round pick in the 2006 First-Year Player Draft out of Navarro College, started the season at Double-A Frisco and hit .333 in 46 games with 13 home runs and 42 RBIs in 186 at-bats. He was then promoted to Triple-A Oklahoma where he is also hitting .333 with 10 home runs and 31 RBIs in 111 at-bats. Overall, he has a .386 on-base percentage and a .643 slugging percentage while striking out 73 times and walking 26 times in 297 at-bats.

He was switched to first base this year, and Daniels said the Rangers are happy with the progress he has made defensively.

"The obvious thing that stands out with Chris is the power potential," Daniels said. "That's a unique tool that he has. He's also been a better hitter and a better defensive player. This is only his second full season of professional baseball, but we've seen him make adjustments in handling left-handed pitchers, improving his pitch selection and his plate recognition. It has been very rewarding. I expect him, though, to have an adjustment period at the big league level."

The Rangers have not made a corresponding move, but it's likely that they'll drop right-handed-hitting first baseman Chris Shelton.