CHICAGO -- Nationals outfielder Jose Guillen left Wednesday night's game against the Cubs with a right hamstring strain. He is listed as day-to-day.
Guillen was running the bases gingerly after grounding out to third baseman Aramis Ramirez in the second inning, but Guillen stayed in the game until Marlon Anderson replaced him in the bottom of the fourth inning.
General manager Jim Bowden said that Guillen will be evaluated by Dr. Tim Kremchek, the Reds' team doctor and senior medical consultant, on Thursday morning.
"We'll have a better read tomorrow morning," said Bowden. "So I'm not going to predict tonight."
Guillen, who is on the trade block, has been hampered by injuries all year. He didn't start Spring Training on time, because of left shoulder and wrist injuries. He's also been bothered by a left oblique strain since early April.
Bill Ladson is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.