OXNARD, Calif. (AP) -- Pro Bowl tight end Jason Witten has a spleen injury and will likely miss the rest of the preseason.

It is unclear if Witten will be ready for the Dallas Cowboys' regular season opener in three weeks, Sept. 5 at the New York Giants.

Coach Jason Garrett said Wednesday that Witten sustained a "slightly lacerated" spleen in the preseason opener Monday night. He said Witten has to remain still as much as possible over the next week so he can heal.

Witten apparently got hurt after he caught a pass from a scrambling Tony Romo and was immediately hit from the side by Oakland linebacker Rolando McClain.

In his nine NFL seasons, Witten has missed only one game, with a broken jaw as a rookie.