The 31-year-old is expected to backup EJ Manuel.
Orton, who has played for the Bears, Broncos, Chiefs and Cowboys in his nine-year career, has thrown for 15,019 yards and 83 touchdowns in 75 games with 59 interceptions. He has a 35-35 record as a starter.
The Cowboys released Orton in July after he missed all of their offseason workouts while contemplating retirement.
- Chris Mascaro