Mike Vrabel has been busy since retiring as a player. He's been working as a defensive line coach with Urban Meyer at Vrabel's alma mater, Ohio State.

Not anymore.

Multiple sources on Twitter indicate that Bill O'Brien is bringing in the former Patriots linebacker to join the Texans' coaching staff. Those sources include Vrabel himself:

I am thankful for everyone assoc with TOSU for 3 great years and my family and I are excited to join the Houston Texans as the LB coach. — Mike Vrabel (@CoachVrabel50) January 9, 2014

With defensive line coach Bill Kollar as the lone man from Gary Kubiak's staff retained by Bill O'Brien, it makes sense that Vrabel will be changing the position he coaches.

Vrabel played eight of his eleven NFL seasons under former Patriots and Chiefs defensive coordinator Romeo Crennel. This move could be another indication that Crennel will serve as O'Brien's defensive coordinator.