Washington Nationals left fielder Bryce Harper warms up before a baseball game against the Philadelphia Phillies at Nationals Park Tuesday, June 3, 2014, in Washington. (AP Photo/Alex Brandon) Bryce Harper warms up before a baseball game against the Phillies on Tuesday. (AP Photo/Alex Brandon)

Nationals Manager Matt Williams is hopeful of a July 1 return for injured Bryce Harper, but admitted there is no firm timetable for the outfielder’s healing left thumb.

“He’s itching and pacing,” Williams said. “It’s one of those things where he’s 21 years old and if it doesn’t heal right it can affect him long term. We want to make sure he’s good before he can get back out here. We don’t know yet. I’d like to see back by the first of July. That’s a good target but we just don’t know how everything else goes.”

Harper has been on the disabled list since April 26 with a torn ulnar collateral in his left thumb that required surgery. The timetable given then was a 6-8 weeks.

Harper has been seeing an occupational therapist and has been doing some strengthening exercises and light baseball activities, Williams said, but has been still limited. Before Tuesday’s game, Harper did some light fielding work on grounders — to “maintain as much motion as he can,” Williams said — but he still can’t hit or play catch. When Harper plays catch, he wears a glove but a trainer catches the ball for him; he only throws.

When Ryan Zimmerman returned from his broken right thumb, he needed only four rehab games. Harper will need more once he is ready because he will have been out longer and required surgery.

“He won’t be able to do as much defensively,” Williams said. “It’ll take a little bit longer to get him back in shape. He’s lifting, doing all his legs stuff and running. He won’t be able to do as much baseball activities so it may take a little bit longer.”

>>> Gio Gonzalez threw a 35-pitch bullpen session on Wednesday and is on track to make a minor league rehab start Friday with Class A Potomac. Williams said Gonzalez is expected to throw between 60 and 65 pitches, but won’t go over five innings, in his rehab start. Gonzalez, who is on the disabled list with left shoulder inflammation, is expected to make only one rehab start and rejoin the Nationals, perhaps for a June 11 start.