Bennett, who sprained the ankle in the third quarter of Saturday night's preseason game against the Minnesota Vikings, is expected to miss two to four weeks.
Bennett was having a productive training camp until his injury on Saturday night curtailed his progress.
It's the second consecutive season Bennett has endured an ankle injury. He sprained his left ankle prior to the start of training camp in 2010 which delayed him from practicing the first week.
Bennett would come back and catch a career-high 33 passes for 260 yards with no touchdowns last season.
With Bennett out, the two main tight ends are starter Jason Witten and John Phillips, who missed all of last season with a torn ACL. Martin Rucker is also trying to make the roster at the position and it hasn't been determined if the Cowboys will go with three or four tight ends on the 53-man roster. The starters are not expected to play in the preseason finale at Miami on Thursday, and that would have given Bennett a chance to start but now Phillips and Rucker will get the bulk of the snaps.
Also, cornerback Alan Ball, who left the game in the first half after returning a blocked field goal for a touchdown, has a bruised left elbow. Team officials don't believe it's serious and if he doesn't play at Miami, it would be more of a precaution.
Calvin Watkins covers the Cowboys for ESPNDallas.com.