Ravens can't afford to let C.J. Mosley walk, but can they afford him?

OWINGS MILLS, Md. -- The Baltimore Ravens face a dilemma with their top free agent this year.

The Ravens can't afford to let middle linebacker C.J. Mosley go elsewhere. But can they afford to keep him?

Baltimore declined to use the franchise tag on Mosley on Monday, according to ESPN's Adam Schefter. This means Mosley will hit free agency if the sides don't strike a deal before March 13.

History indicates the Ravens will find a way to keep him. In their 24-year existence, the Ravens have never allowed a first-round pick who reached multiple Pro Bowls to go elsewhere after his rookie deal expired.

But contract numbers -- and not the team's track record -- will dictate whether Mosley will remain in Baltimore. Even coach John Harbaugh acknowledged at season's end that there are "limitations with the money" after expressing his desire to keep Mosley.

Mosley is the top tackler for the NFL's No. 1 defense. He is a four-time Pro Bowl player. He is an underrated leader. The Ravens have to determine whether all of that means Mosley should be paid at the same level as the Carolina Panthers' Luke Kuechly and the Seattle Seahawks' Bobby Wagner.

It is possible Mosley will command $11 million or $12 million per season, and it's not about who's the best middle linebacker in the game. It's about who is the best middle linebacker available in free agency, and that title this year belongs to Mosley.

The Ravens have an estimated $18.5 million in salary cap room, putting them among the 11 teams with the least amount of space, according to Over The Cap. Baltimore has so many needs -- at wide receiver, interior offensive line, pass-rusher and running back -- that it could be a challenge to give top dollar to Mosley. Teams such as the Denver Broncos, Oakland Raiders and Arizona Cardinals all have $34 million or more in cap room, and that equates to more spending power.

New Baltimore general manager Eric DeCosta wants to be financially responsible with the salary cap, and the general rule in the league is that teams should spend their money on pass-rushers and cornerbacks. In this case, an argument can be made that Mosley was the most indispensable player on the NFL's top-ranked defense.

When Mosley was carted off in Cincinnati last season, Baltimore allowed touchdowns on the first four drives without him. When the season was on the line, Mosley made the biggest play of his career, intercepting Baker Mayfield in the final minutes of the finale to clinch the AFC North.

Mosley, 26, has impacted the defense in a variety of ways. He is one of two players to record at least 500 tackles, 8 sacks and 8 interceptions since he entered the NFL in 2014. (Kuechly is the other.)

A first-round pick in 2014, Mosley has gone to the Pro Bowl in four of his five NFL seasons, which puts him in select company. Seven of the 11 linebackers who were named to Pro Bowls at least four times in five seasons are in the Hall of Fame.

The biggest knock on Mosley has been his pass coverage. But he posted career lows in passing yards allowed (408), yards per reception (9.3) and yards after the catch (190), according to Pro Football Focus.

The Ravens have a history of keeping first-round picks who lived up to expectations and went to more than one Pro Bowl: Jonathan Ogden, Ray Lewis, Peter Boulware, Chris McAlister, Todd Heap, Ed Reed, Terrell Suggs and Haloti Ngata were all signed before their rookie deals expired.

If the Ravens can't retain Mosley, they will either turn to Kenny Young, a fourth-round pick from a year ago who flashed at times, sign a veteran free agent or draft a prospect. Baltimore would hope someone could fill Mosley's void; there would be uncertainty in the middle of the defense, the longtime strength of the franchise.

The Ravens are in this predicament because they didn't place the franchise tag on Mosley, which would have put the team in a bigger financial bind. Under the tag, Mosley would've made $15.4 million this year, which is almost $5 million more than the highest-paid middle linebacker in terms of base salary. (Wagner is scheduled to earn $10.5 million this season.)

The Ravens need to keep Mosley. Baltimore just knows it can't do so at any cost.