NASHVILLE, Tenn. — Tennessee Titans outside linebacker Arden Key is facing a six-game suspension for violation the league’s rules against performance-enhancing drugs, a team source confirmed to ESPN on Tuesday.

Titans coach Brian Callahan was asked about Key’s suspension after practice on Tuesday.

“I don’t have much to comment on it until that comes out from the league,” Callahan said. “It’s not something that you want to hear but we don’t have a choice. We have to go play football with what we have.”

The loss is a critical blow to the Titans defense as Key was set to be a starter at outside linebacker opposite Harold Landry. Key’s six sacks were the third-most by a Titans player last season. The seventh-year veteran signed a three-year, $21 million contract with the Titans last March.

The Titans will be without Key for a tough stretch of games against the Chicago Bears, New York Jets, Green Bay Packers, Miami Dolphins, Indianapolis Colts, and Buffalo Bills. Tennessee will turn to veterans Rashad Weaver and Caleb Murphy along with rookie Jaylen Harrell to fill in for Key. The Titans also signed Broncos 2015 first-round pick Shane Ray last week.

Former Titans defensive lineman Denico Autry found out yesterday that he’s facing a six-game suspension. Autry signed a two-year contract with the Texans in March.

The news of Key’s suspension was first reported by NFL reporter Paul Kuharsky.