Ryan Zimmerman continues to progress since injuring his hamstring July 22 in Colorado. (Ron Chenoy/USA TODAY Sports)

Third baseman Ryan Zimmermann stepped up his rehab from a torn right hamstring this week after he underwent a “very positive” MRI exam Monday, Manager Matt Williams said.

Zimmerman still has yet to swing a bat, Williams said, but he increased his strengthening regimen and started jogging. If he continues progress, Williams said, the next step is sprinting and taking batting practice.

“It’s healing up really nicely,” Williams said. “The first test is him running. And then it’s bases, certainly [batting practice] and getting his swing back and all that. But he’s making the progress he should make.”

Zimmerman has already missed 35 games since he torn his hamstring trying to beat out a groundball July 22 in Colorado. The Nationals are hopeful Zimmerman will return in the middle of September.

The Nationals have thrived without him after acquiring second baseman Asdrubal Cabrera to take his place in the lineup. Whenever Zimmerman returns, Williams will face another playing-time dilemma: where will Zimmerman fit?

Anthony Rendon has been the Nationals’ most valuable player at third base. Cabrera has been steady at the plate and dazzling in the field. Zimmerman played left field earlier this season, but that spot is occupied by Bryce Harper.

If the Nationals make the World Series, they’ve got their DH in American League parks. In the interim, it seems possible Zimmerman could come off the bench as a late-game, pinch-hitting weapon. Their defense may be too good to break up at the moment, especially as Zimmerman regains his timing.

But that’s a question that will be in answered in a few weeks. For now, Zimmerman is on pace to join a team that has the best record in the National League despite playing only 53 games with him this year.