CINCINNATI -- Taking ground balls at first base was not supposed to be part of Bryce Harper's rehab from Tommy John surgery.

But Harper was out early Thursday working with infield coach Bobby Dickerson.

Phillies manager Rob Thomson was impressed with what he saw.

"I didn't see him yesterday, but I was out there today," Thomson said. "He looked fine. [Dickerson's] a great coach. Guys take to him like this. Bryce puts a lot of work in. He's got as good as a chance at anybody to do it.

"He wants to do it."

If Rhys Hoskins hadn't suffered a season-ending knee injury, Harper wouldn't be working out at first, but Harper volunteered.

Harper will first return as a designated hitter, likely before the All-Star break, but it would seem logical that the throws from first are less stressful than throws from right field. However, Thomson isn't sure how much quicker Harper could return to the field if it's at first.

"I don't have a sense of that," he said. "I have never really gone through this before in all my years. I'm not sure how long it's going to take him to play the outfield or how long, if he plays first base, it will take."