Source: Ravens' Calais Campbell (knee) longshot for Falcons

OWINGS MILLS, Md. -- The strong Baltimore Ravens defense isn't expected to be at full strength for Saturday's game against the Atlanta Falcons.

Ravens defensive end Calais Campbell could miss some time with a left knee injury and is considered a long shot for Saturday, a source told ESPN's Jeremy Fowler. Campbell was injured with 11:47 left in the fourth quarter of Saturday's 13-3 loss in Cleveland and was wearing a bulky brace on his left knee in the locker room.

A six-time Pro Bowl defender, Campbell has been an inside force for a Baltimore defense that has carried the team recently. The Ravens have allowed allowed 13.3 points over the last six games, the second fewest in the league over that span.

In his 15th NFL season, Campbell was having a resurgent year with 36 tackles, 5.5 sacks and one blocked field goal. He is one sack shy of reaching 100 for his career.

In addition to Campbell, cornerback Marcus Peters could also be sidelined as well. He left Saturday's game with a strained calf and did not return.

The Ravens (9-5), who fell into second place in the AFC North, can clinch a playoff berth Saturday with a win over Atlanta and a combination of two losses from three AFC East teams (the Jets, Dolphins and Patriots).

It's possible quarterback Lamar Jackson returns this week after missing two games with a sprained knee. Ravens coach John Harbaugh is scheduled to talk to reporters Monday at 3:30 p.m.