Kitna last played for the Cowboys in 2011. He has been teaching and coaching high school football in Tacoma, Wash.
The Cowboys have not ruled out Romo from playing Sunday against the Philadelphia Eagles, despite a back injury. However, sources have told ESPN's Adam Schefter and Chris Mortensen that Romo will not play this season and needs back surgery.
Kyle Orton will start if Romo can't play. Sources said Romo had an epidural injection on Monday, and the hope is it quells the back troubles enough for him to be able to play.
The Cowboys worked out David Carr, John Skelton, Tyler Thigpen, Caleb Hanie and Richard Bartel on Tuesday, but elected to go with Kitna, who is 41. Kitna knows the Cowboys offense as well as most of the personnel, but he has been out of the NFL for two seasons.
In 15 seasons with the Cowboys, Detroit Lions, Cincinnati Bengals and Seattle Seahawks, Kitna started 124 games, throwing for 29,745 yards with 169 touchdowns and 165 interceptions. He started nine games for the Cowboys in 2010 after Romo suffered a broken collarbone and threw for 2,365 yards with 16 touchdown passes and 12 interceptions.
The Cowboys needed to sign a quarterback to at least get through practice with Romo hurt. They have not had an extra quarterback since losing Alex Tanney off the practice squad last month.