The Detroit Lions underwent some major changes with their coaching staff this offseason. That said, some personnel adjustments were to be expected.

It goes without saying that quarterback Matthew Stafford will remain under center moving forward. The Lions have now seemingly solidified the quarterback group with the signing of Matt Cassel, according to NFL Network's Mike Garafolo:

Lions are signing QB Matt Cassel, sources say. Former Patriots QB joins former Patriots Bob Quinn and Matt Patricia in Detroit.

The addition of Cassel makes sense for a number of reasons. First one being, of course, is his New England connection to general manager Bob Quinn and head coach Matt Patricia.

The three had been together during Cassel's first four seasons in New England. He even started an entire season for the Patriots in place of an injured Tom Brady before making his rounds as a starter elsewhere. Since then, he has become a solid backup as an NFL journeyman after stints with the Kansas City Chiefs, Minnesota Vikings, and Dallas Cowboys. Cassel now comes to Detroit after spending the last two seasons with the Tennessee Titans.

He will likely serve as the backup to Stafford next season. However, Cassel may still have to compete with fellow backup quarterback Jake Rudock for second-string duties. It goes without saying that Stafford is as tough as they come when it comes to playing through injury. However, having a solid backup will allow the Lions some flexibility when it comes to taking care of their franchise player.