The San Francisco 49ers are expected to name linebackers coach DeMeco Ryans the team's new defensive coordinator after Robert Saleh was hired as the head coach of the New York Jets, according to NFL Network's Ian Rapoport. 

Ryans, 36, is a former second-round pick of the Houston Texans who played in the NFL from 2006 to 2015 before retiring. It's a quick rise for the Alabama product. Ryans joined the Niners as a defensive quality coach in 2017 and was promoted to inside linebackers coach a year later. Now he takes over a defense that finished fifth overall in 2020. 

Considering Saleh has been one of the hottest names on the coaching market for some time now, the Niners had plenty of opportunity to prepare for a change at defensive coordinator. 

Promoting Ryans not only helps head coach Kyle Shanahan keep his staff as intact as possible, but it should also help the players feel just as comfortable with the playbook. 

That's not to say Ryans will get to work with the exact same defense Saleh had. 

Among the upcoming decisions for the salary-cap-strapped franchise will be which players the defense can't live without. 

Cornerbacks Richard Sherman, K'Waun Williams and Jason Verrett and defensive linemen Solomon Thomas, Ronald Blair, Ezekiel Ansah and Kerry Hyder are all expected to hit free agency. That's to say nothing of fullback Kyle Juszczyk, center Ben Garland and running back Jeff Wilson Jr. on the offensive side. San Francisco simply cannot keep all of them, especially after it presumably re-signs left tackle Trent Williams.

Sherman seems to understand as much and doesn't expect to return—though he has expressed a desire to make it work. 

To keep the unit elite, Ryans will have to develop new stars. 

It's not an easy task, but it's one the Niners feel comfortable trusting him with.