Justin Verlander will be sidelined for weeks with a left hamstring strain just days before the 43-year-old was set to return for the Detroit Tigers from a separate injury.

Verlander had been on the injured list since April with left hip inflammation and was scheduled to start Sunday before sustaining the hamstring injury during a bullpen session Wednesday.

"This is not a matter of days," said AJ Hinch. "It's a matter of weeks. We're going to need a full rehab process to get him back to throwing again. Obviously, frustrating news for him and for us, given the excitement that was building around his start on Sunday."

Verlander described the injury as sudden, cutting short a bullpen outing that had otherwise gone well.

"My hip actually feels fairly good," said Verlander, according to MLB.com. "All of a sudden, my hamstring was bugging me and I had to cut my bullpen short. Anytime I'm not able to get my work in, it means something's definitely off, so we decided to get it looked at, and there's a strain. Just really unfortunate, man. It just sucks. I don't know how else to say it."

The three-time Cy Young winner and 2011 American League MVP is the oldest active player in MLB. In his lone start this season, Verlander allowed five runs and six hits over 3⅔ innings in a loss at Arizona.

Detroit also placed outfielder Wenceel Perez on the injured list with facial fractures after he was struck by an exercise band that came unhooked during a postgame workout in Houston.