"I have no clue when I'll be back," he said Sunday. "I really don't. Your guess is as good as mine."
Hamilton ran into the left-field wall at Minnesota on Saturday and bruised his ribs. He said all he can do for now is apply ice and hope he feels better.
"I feel like I've been in a car wreck," he said.
Hamilton said he felt the same way last year after running into a wall at Toronto, an injury that forced him to miss 13 games.
Hamilton is hitting .361 with 31 home runs and 97 RBIs.
"Right now I want to get to a point as quickly as possible where I can swing, where I can do other things on the field (and) not going to make me have any setbacks," the All-Star outfielder said. "When I get to that point, I'll get after it."
Neither Hamilton nor Texas manager Ron Washington could put a timetable on when the slugger may return.
"With those ribs, you've got to give him a few days," Washington said. "I'm not going to question Hamilton. I'd say it is day-to-day."
The Rangers lead Oakland by eight games and have 26 games left in the regular season.