Jones says Cowboys set to place starting quarterback on injury reserve

"It's iffy," Jones said of the timeline for Prescott to return from a hamstring injury he suffered in the third quarter of the Cowboys' 27-21 loss to the Atlanta Falcons on Sunday.

"But it's (an) extended period of time ... it's likely we'll IR him, so we'll see how his rehab goes."

Prescott, who was sacked three times as he played under pressure throughout Sunday's game, exited in the third quarter after feeling "something I've never felt before" in his leg.

"I felt it when I was getting up from the run," Prescott said. "I can't even say I felt it running. Maybe it was the tackle or something on the tackle.

"When I was standing up from that, I felt something, but didn't think it was much. It was a physical game and, a lot of times, you feel different things and then they go away."

But Prescott was, in fact, unable to continue, with Cooper Rush replacing him for the rest of the game.

Cowboys coach Mike McCarthy had confirmed on Monday that Prescott wouldn't be available for Sunday's game against NFC East rivals Philadelphia, who posted their fourth straight victory on Sunday.