Tony Romo CBS

Tony Romo is officially out at CBS Sports ... ending his nine-year run with the network months after his highly publicized OWI arrest.

CBS confirmed to TMZ Friday it had "mutually agreed to part ways" with the former Dallas Cowboys quarterback ... thanking him for his contributions and wishing him the best moving forward.

J.J. Watt -- who has filled in for Romo so far this season -- will remain in the booth alongside Jim Nantz and Tracy Wolfson.