Buffalo Bills leading pass catcher Charles Clay went down early in Sunday’s loss to the Cincinnati Bengals. The tight end was hit on the knee after making a catch. Dr. David Chao has reviewed the video and expects Clay to miss a month.

“By video, Clay suffered at least a MCL sprain, but there is worry for an ACL tear,” wrote Chao. “At a minimum, the MCL sprain will have him out of several weeks. The worst-case scenario is a season ending ACL tear in addition.”

Chao went on to mention that the Bills already know the extent of Clay’s injury after a physical examination yesterday. The team may still send him for a confirmation on MRI, so we might not get a straight answer from head coach Sean McDermott this afternoon.

The Bills will probably need to look outside the organization for reinforcements. Clay was replaced by Nick O’Leary in the game Sunday and he acquitted himself well. Logan Thomas only has a few games of experience under his belt at tight end. Khari Lee has been inactive since he was claimed by the Bills on waivers in September. Lee does have experience, having played in seven games for the Chicago Bears in 2015. He was only active for eight games with the Detroit Lions a year ago, and was targeted on just one pass. He has one NFL reception for seven yards.

Clay missed one game last year for the birth of a child and three the year before with a back injury. While he’s had problems with his knees in the past, he hasn’t missed any time in Buffalo due to the injury.

Update: (1:20 p.m.)