Martavis Bryant is facing a yearlong suspension from the NFL, his agent confirmed.

The suspension is related to NFL drug testing, a source told ESPN. Bryant's agent, Tom Santanello, confirmed Saturday that the talented receiver plans to appeal the suspension.

Another of his agents, Brian Fettner, told USA Today Sports that Bryant, who served a four-game suspension last season for violating the league's substance abuse policy, is fighting depression and plans to enter rehab Sunday for evaluation.

"We're all stunned, me included," Fettner told USA Today Sports. "We clearly miscalculated the issue. His isn't a party issue. It's a coping issue and a depression issue, and he's got to take care of it.

"This is the biggest cry for help I've ever seen. And that hurts. It hurts us to see. He's 24 years old and he's got to get right, whatever it is. If you talk to anybody's family that has depression, they will be talking about these same things -- the [despondence], the withdrawal, the head-in-the-sand despair -- just trying to cope."

After returning from his four-game suspension, Bryant had a productive 2015 season for the Steelers, hauling in 50 receptions for 765 yards and six touchdowns in 11 games.