The NFL is investigating why Tony Romo hasn't been on the Dallas Cowboys' injury report with his rib issue.

Romo said after Thursday night's 41-28 win against the Chicago Bears that he was playing with a broken rib. However, multiple sources say Romo misspoke and that he had torn rib cartilage, not a break.

A team is subject to a fine if the league finds it did not comply with its injury report rules. In 2009, the New York Jets were assessed $125,000 in fines for failing to put quarterback Brett Favre on the injury report after he revealed he played the final month of the 2008 season with a torn biceps tendon.

Romo has been listed on the injury report all season because of his back.