"Chris needs to get things together," manager Ron Washington said. "He needs to get into a little less pressure situation. [We're] giving up a lot of defense with that move."
Washington said the Rangers are expected to give Hank Blalock the majority of at-bats at first base, though Andruw Jones could be an option there as well.
Hamilton has hit .148 (4-for-27) through six Minor League medical rehabilitation games.
The RedHawks played a doubleheader on Sunday after Saturday's game was rained out. Hamilton went 2-for-4 in the RedHawks' first game with a double and a triple and the game-winning run scored. He then went 0-for-3 in the second game with a walk and a strikeout.
"He's been down there and played [six] ballgames," Washington said. "It was time for him to come help us out."
Davis has stayed at the Major League level because of his excellent defense, but the Rangers could no longer live with his lack of offense.
He has posted a .202 batting average this season.
"What I'm doing is not working," Davis said. "It was definitely not the Chris Davis that they thought they were getting. They know how productive I can be and I haven't been that guy. We all know how this year has gone. It's no secret. It's good that I can clear my head, take my time, figure out what's going on and get back here.
"I want to go out, work my tail off, get squared away and get back up there. I want to be a part of this team."
The Rangers are now carrying six outfielders -- Julio Borbon, Marlon Byrd, Nelson Cruz, David Murphy, Hamilton and Jones. Washington wanted to have Borbon's talents in the lineup.
"He gives us some speed," Washington said. "I have another guy to bunt."
Daniel Paulling is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.