PHILADELPHIA -- Aaron Nola's most recent MRI was clean, reports Phillies general manager Matt Klentak.
The right-hander will throw a bullpen session this weekend that will dictate his path back to the starting rotation, one that will likely include a brief stop in the Minors.
Nola was sent home from the Phillies' recent road trip when he experienced back spasms during a throwing session. He hasn't pitched in a game since April 20.
"He's been down long enough that he'll likely have to go on a rehab assignment before he comes back with the Major League club," Klentak said. "But certainly that's good news."
The Phillies have also been without veteran left fielder Howie Kendrick for the last three weeks. Best-case scenario, according to Klentak, is to have Kendrick begin his rehab assignment mid to late next week.
Meanwhile, Kendrick has been putting in the work to seamlessly transition back into the starting lineup, whether that be back in left field or somewhere else.
"He's been working hard at first, second, third, outfield," Phillies manager Pete Mackanin said. "He looks like an 18-year-old kid trying to make a team, just full of energy."
Aaron Altherr's stellar play in Kendrick's absence has put the Phillies in a difficult, although enviable, position. Both have been among the team's best hitters early on.

"That [versatility] was one of the reasons that Howie was an attractive target for us in the offseason," Klentak said. "He could spend a month as your everyday left fielder, then a month he could play first, he can play third, he could play left, he could play second, he could play a lot of different positions."
Thompson called up to strengthen 'pen
Jake Thompson was recalled from Triple-A Lehigh Valley to serve as long relief for the bullpen. His stay with the Phillies is not expected to be long; Mackanin called it "most likely" a short-term deal. Utility player Ty Kelly was optioned in a corresponding move.
Since he normally pitches as a starter, Thompson can provide length and take a load off the arms the Phillies have been heavily relying on.
"We need to protect that bullpen," Mackanin said.
Thompson struggled in his first two Minor League starts this season (28.93 ERA), and has returned to the full windup that Phillies pitching coach Bob McClure transitioned him away from last season.
Since then, he's posted a 0.98 ERA in three starts.