Taylor Decker injury leaves Lions with questions at left tackle

The Lions had their fourth straight impressive win on Sunday in Cincinnati, but there was an area of concern at left tackle, where starter Taylor Decker was out with a shoulder injury and backup Giovanni Manu was not up to the task of protecting Jared Goff's blind side.

Lions coach Dan Campbell described Manu's performance as "up and down," but that's being generous. Manu did not play well, and if he's going to fill in for Decker again, the Lions need him to play a lot better.

"There were some [plays] that weren't good, and he'll learn from them, and he's got to learn from them," Campbell said of Manu.

Campbell said that if Decker misses more games, they may keep Manu on the sideline and look for a new replacement. That could be Dan Skipper or Devin Cochran, the other offensive tackles on the team. Campbell stressed that the Lions want Decker back on the field, but only when they're sure he won't aggravate his injury.

"We'll see where Decker is at - that's always our first choice, to see where Decker is, but I don't want to put Decker in there for a few games if that means he won't be available at the end of the year. That makes no sense," Campbell said.

Campbell said Decker has been trying all year to tough it out with his shoulder injury, but in each of the first four games of the season his shoulder felt a little worse, and the Lions finally decided they needed to give him time to heal.

"Every week, the recovery has been less and less," Campbell said. "There's diminishing returns every week and we felt like we need to give this guy a little time, and I don't know how long. But this is so we get him back. Let't get some strength in the shoulder so he feels good."

The Lions will feel a lot better when a healthy Decker is protecting Goff again.