Has C.J. Mosley become Ravens' most indispensable defender?

CINCINNATI -- The Baltimore Ravens and middle linebacker C.J. Mosley have yet to reach an agreement on a contract extension.

Perhaps there will be more urgency to get a deal done after how the Ravens' defense initially crumbled without Mosley in Thursday night's 34-23 loss to the Cincinnati Bengals.

With Mosley, the Ravens forced a three-and-out. When Mosley was carted off with a knee injury, Baltimore allowed touchdowns on the first four drives without the three-time Pro Bowl player.

Mosley wouldn't have had coverage on A.J. Green on any of the Bengals wide receiver's touchdown catches. Cornerback Jimmy Smith's suspension for violating the NFL's personal conduct policy factored into Baltimore's pass defense.

Mosley's absence, however, created a domino effect of confusion that was felt throughout the defense.

"That’s our defensive leader," defensive tackle Michael Pierce said. "It’s big. It can’t be overstated."

Mosley has been repeatedly called the quarterback of the defense by coordinator Don "Wink" Martindale. Ray Lewis named Mosley the best current middle linebacker in the game.

All of this was underscored when Mosley leaped over Cincinnati wide receiver Tyler Boyd, who was on the ground, and landed awkwardly. He limped off the field and was carted off.

Inside linebacker Patrick Onwuasor, who is three years removed from playing safety in college, took over the defensive calls. The result: The Ravens allowed 28 points in the first half, their most given up before halftime since 2012.

Safety Eric Weddle took over the calls after halftime, and the defense settled down. The hole, however, had already been dug.

"All of us didn’t really know what was happening, but that’s not really our job," linebacker Terrell Suggs said. "When something is going on, we just got to adjust. We’re a very capable team of doing that, of making an adjustment."

Mosley was diagnosed with a bone bruise, and an MRI on Thursday night revealed no ligament damage, according to coach John Harbaugh. There was no definitive timetable given, but Harbaugh said the injury doesn't look to be long-term.

A bone bruise could be a multi-week injury. Baltimore hasn't played without Mosley often, but it has been problematic when he's been out. The Ravens were without Mosley for two games in 2016 because of a calf injury, and they lost at the Jets and Giants while giving up a total of 51 points.

If Mosley is sidelined for a period, it goes beyond losing a playmaker for Baltimore. His absence leaves the Ravens with two young players in the middle: Onwuasor, a third-year player who went undrafted, and Kenny Young, a rookie fourth-round pick.

"Those guys played hard," Harbaugh said. "They fought, they really did, but they didn’t play perfect. That’s going to hurt you for sure, and it did. It hurt mainly in coverage more than anything."

Mosley is in his fifth-year option, making $8.7 million this season. He is scheduled to become an unrestricted free agent in March.

Entering this season, Mosley wrote a list of goals on a piece of paper that he taped to his locker, from leading the NFL in tackles to becoming NFL defensive player of the year. Losing that type of a player leaves a large hole in the middle of the defense.

A couple of areas where the Ravens have to improve without Mosley is stopping the run and covering tight ends. After Mosley was sidelined, Bengals running back Joe Mixon ran for 85 yards on 20 carries and Cincinnati tight ends combined for seven catches for 79 yards. That yardage accounted for 43 percent of the Bengals' offense.

"It was very tough, because those are things that you don’t expect," Young said of the loss of Mosley. "But one of the things that we took pride in this year is getting guys prepared. We just have to execute as a whole. C.J. is one guy. He’ll be fine. And the rest of us just have to go out and ball out for him."