PITTSBURGH -- Steelers wide receiver Sammie Coates will miss the start of training camp after undergoing a knee scope last week, a source told ESPN.

Coates, who suffered a knee injury while training in the offseason, is a candidate for the physically unable to perform list but could return in mid-August, depending how the knee heals.

Coates, who trained with longtime NFL receivers coach Jerry Sullivan this summer, hopes to rebound from a difficult 2016 season. Coates posted 421 receiving yards in the first five games, but then injuries to his fingers and groin affected his production. The groin injury required offseason surgery.

The third-round pick from 2015 will compete for a spot in the Steelers' vertical passing game.

"I'm starting to get my speed back," Coates said during team workouts in June. "I'm getting there. It's a process. That's what this process is for, to get your body back so you can compete during camp."