Yet, Witten still hopes to play Sunday against the NFC East-leading and rival New York Giants.
"I hope I can get out there and help," Witten said in the locker room Thursday before practice. "It's a big game obviously, and do my part."
With the Cowboys facing the prospect of having more talent sidelined by injuries than they have competing on the field against the defending Super Bowl champions, Witten seems determined to underscore his reputation as one of Dallas' toughest players.
Whether Witten is able to play will depend upon not only his pain tolerance, but his ability to protect the football while wearing additional equipment over the injured area.
Witten left in the second quarter of Sunday's pivotal 13-9 victory over the Tampa Bay Buccaneers and briefly returned in the second half before pain forced him to the sideline.
The severity of the injury was revealed through Monday's MRI exam, which contradicted the results of the X-rays taken during the game.
Witten leads the Cowboys in receptions with 46 and receiving yards with 549 and has two touchdowns. The Cowboys are mired in a terrible offensive slump -- with backup quarterback Brad Johnson starting for injured Tony Romo, the Cowboys have been held to fewer than 20 points in back-to-back games for the first time since October 2005.
Witten has consistently been one of Romo's most reliable targets. But if he is unable to play against the Giants or is forced out of the game, Witten's absence would be even more of an issue for Johnson, whose lack of arm strength forces him to look for his underneath receivers more frequently.
Johnson expects to start his third straight game Sunday while Romo recovers from a fractured pinkie on his throwing hand.
Rookie Martellus Bennett and Tony Curtis back up Witten.
Throughout his career, Witten has been one of the Cowboys' most dependable players and fiercest competitors. Last month, he took painkilling injections to continue playing with a shoulder injury.
He has missed one game in his NFL career. That occurred when he fractured his jaw as a rookie in 2003, with Bill Parcells as the Cowboys' coach. Witten underwent surgery to install two plates in the jaw, and was back on the field after sitting out one week, even though he was still unable to eat solid foods at the time.
His competitiveness became apparent last season during a 53-yard reception against the Philadelphia Eagles, as Witten continued running without his helmet for at least 20 yards after it came off during a collision with safety Quintin Mikell and cornerback Joselio Hanson.
The Cowboys, with one of the most talent-heavy rosters in the league, were considered a Super Bowl favorite, but they have been decimated by injuries. In addition to Romo and possibly Witten, the Cowboys are without Pro Bowl defensive backs Terence Newman and Roy Williams, cornerback Adam Jones, punter Matt McBriar, and they have been playing without left guard Kyle Kosier.
In addition, cornerback Anthony Henry tore his quadriceps against the Buccaneers, but the Cowboys are optimistic rest and treatment will
be enough for him to play Sunday. If Henry can't play, Orlando Scandrick would start opposite fellow
rookie Mike Jenkins.
Ed Werder covers the NFL for ESPN. Information from The Associated Press was used in this report.