Romo has been out since he suffered a fractured left collarbone eight weeks ago against the New York Giants. He was expected to miss 6-8 weeks.
The Cowboys have been waiting to see if the injury would heal in time for him to play at least the last two regular-season games before making any decision on Romo's status for the rest of the season. Owner/general manager Jerry Jones said Romo's recovery time has gone slower than expected.
"If he were healthy, he would practice," Jones said after Sunday's victory over the Washington Redskins. "We are a little behind where I thought we would be on how healthy he is."
Romo has done some light throwing at practice, but he has discomfort throwing the ball with force and has issues sleeping on the left shoulder.
If the Cowboys put Romo on IR it would open a spot on the active roster. The Cowboys could use that spot to take a player off another team's practice squad.
Dallas could also choose to promote one of its own practice squad players, such as Robert Brewster, Ross Weaver or Alex Daniels.
The status of several other Cowboys is uncertain because of injuries.
Rookie linebacker Sean Lee and starting safety Gerald Sensabaugh left Sunday's game against the Redskins after suffering concussions. Both players need to pass league-mandated tests to become eligible for Saturday's game at Arizona.
The short week could hurt their chances of playing.
"They have to be symptom free as they go through each of the stages," interim head coach Jason Garrett said Monday. "So we'll just go through that process."