ARLINGTON -- Rangers third baseman Adrian Beltre suffered a setback while running the bases for the second consecutive day on Saturday, re-aggravating his strained left hamstring.

Rangers doctors estimate the new injury could cost Beltre three additional weeks.

He was going through normal baserunning drills at full speed, practicing making hard turns around first and then exploding to second, but on one attempt he appeared to come up lame on his left hamstring.

"He'll see Dr. [Keith] Meister tonight, and we'll see where it goes from there," Rangers manager Ron Washington said.

An MRI showed that Beltre had re-aggravated the hamstring.

Beltre had been focused on being ready as close to Sunday as possible, as that was going to be the first day he could come off the disabled list, although he likely would have gone on a rehab stint before returning.

"It just happened in the process," Washington said.