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.