Decker's shoulder injury is actually a torn labrum, and the timetable for recovery is four to six months, according to an NFL Network report. Decker injured the shoulder last week and had surgery on it Monday, leaving the Lions with a massive hole on quarterback Matthew Stafford's blindside.
Detroit signed journeyman veteran Tony Hills on Thursday to compete for the position with Cornelius Lucas, Joe Dahl and Corey Robinson. Lucas and Dahl shared No. 1 left tackle reps at the open-to-the-media OTA on Tuesday after the franchise announced Decker's injury.
Decker's agent, Shannon Polk, declined comment to ESPN on the NFL Network report Friday.
The theoretical timetable in the NFL Network report would mean Decker could miss anywhere from four to 12 games this season. Lions coach Jim Caldwell said Tuesday he didn't think Decker's injury would end his 2017 season, but he declined to provide specifics beyond that. Caldwell said the franchise would provide an update on Decker in the fall.
Decker played every snap for the Lions at left tackle last season, forcing the franchise to move Riley Reiff to right tackle last season. Reiff left in the offseason to become the Minnesota Vikings' left tackle. The Lions ruled out moving right tackle Rick Wagner, who signed with the club in free agency, to left tackle to offset Decker's loss.
"Just kind of the nature of our game," Caldwell said. "You've got to adjust. That's one of the things that I think our personnel office does a great job of, I think our players do a tremendous job of. We'll adjust and keep moving."