IRVING, Texas (AP) -- Dallas Cowboys quarterback Tony Romo has a broken finger on his throwing hand and could be out for up to four weeks.

Romo broke his right pinkie on the first play of overtime in a 30-24 loss at Arizona on Sunday, according to a posting on the team's official Web site. A team spokesman didn't immediately return a call seeking comment Monday.

The injury leaves the Cowboys (4-2) with 40-year-old Brad Johnson as the starter. Johnson, who won a Super Bowl with Tampa Bay, hasn't started a game since 2006 in Minnesota.