The Indianapolis Colts’ offensive line won’t be at full strength when they host the Buffalo Bills in Week 10. They’ll be missing a major piece to their puzzle up front.

On Tuesday, the team placed veteran center Ryan Kelly on injured reserve, according to NFL Network’s Tom Pelissero.

Kelly, a Pro Bowler in four of the past five years, will miss at least the next four games for the Colts after suffering a knee injury.

Colts running back Jonathan Taylor will be looking to get back on track on the ground this week despite the loss of their team captain at center. In last week’s loss to the Minnesota Vikings, he was held to 3.7 yards per carry and totaled just 48 yards.

Taylor will attempt to right the ship while running behind rookie center Tanor Bortolini on Sunday. But, even with a fourth-round rookie handling the snaps, the Bills defensive line will still be tested.

Bortolini, a former Wisconsin Badger, will start at center for Kelly for the third time this year. He has fared well while at center so far. In 160 total snaps, his 66.3 Pro Football Focus grade ranks 18th among 57 qualifying centers. Bortolini has given up zero sacks on just one pressure allowed and has committed just one penalty.

The Bills’ defensive line has seen its struggles as of late and they recently lost defensive linemen DeWayne Carter and Dawuane Smoot to IR. They did bring back free-agent defensive tackles Jordan Phillips and Quinton Jefferson on Wednesday, but they are a unit on the team that has left a lot to be desired.

How the Bills’ front, particularly Ed Oliver and DaQuan Jones, perform going up against the rookie is now a key matchup to watch in Week 10.