Ryan Zimmerman. (AP Photo/Alex Brandon) Ryan Zimmerman. (AP Photo/Alex Brandon)

With his right thumb still in a splint, Ryan Zimmerman has been in the Nationals clubhouse before games the past few days. He has gone for weekly x-rays on his fractured right thumb, a check-up to make sure the bone is healing properly. His thumb is still immobilized but he is exercising.

Zimmerman has been running on a treadmill in a pool, which ensures that his broken finger won’t be bouncing around a lot, Manager Matt Williams said. He has been working out his legs and maintaining his cardiovascular activity. The third baseman still can’t grip with his right hand.

He can field groundballs, Williams  said, but not with his right hand.

Zimmerman broke his thumb diving back to second base on a pickoff on April 12 in Atlanta. The timetable then was four to six weeks and Williams said Wednesday that Zimmerman is on schedule.

>>> Scott Hairston took on-field batting practice on Wednesday for the first time since landing on the disabled list on April 6 with a strained oblique. Hairston had been swinging in the batting cages in recent days but Wednesday was another step forward for the backup outfielder.

Hairston reported no pain after the early batting practice session, Williams said. “We’ll see how he reacts [Thursday],” he said. Hairston would need to play in minor league rehab games before returning, Williams said.