WASHINGTON -- Nationals shortstop Cristian Guzman had a precautionary MRI on his left thumb on Wednesday and the results were negative. He is listed as day-to-day.

Guzman said he hurt his thumb while playing against the Reds during the first week in July and aggravated it last week against the Giants. Guzman likely will not start in Thursday's finale with the Phillies, but he is available for defensive and pinch-running duties.

Meanwhile, general manager Jim Bowden said that first baseman Dmitri Young is not doing well with controlling his diabetes. Bowden declined to give a timetable on Young's return.