Romo immediately departed for the locker room to undergo X-rays.
"The X-rays were inconclusive. So we don't know that much at this point," head coach Jason Garrett told reporters after the game. "We'll have further tests tomorrow and we'll see what those show. So taking it day by day, don't know much right now."
NFL Media Insider Ian Rapoport reported Friday morning that the Cowboys had not yet given up hope that Romo could return this year. Tests late Thursday were inconclusive, Rapoport added, and Romo will undergo a CT scan Friday.
It's worth noting that Romo was told by doctors that he was still at risk of re-breaking his collarbone when he returned to face the Miami Dolphins two weeks ago, FOX Sports' Jay Glazer reported.
Romo had a nightmare first half versus Carolina's opportunistic defense, throwing three interceptions, including two that were returned for touchdowns. Romo tossed five interceptions in seven quarters since his return to the lineup.