Eagles coach Chip Kelly said he has decided not to play quarterback Sam Bradford on Sunday in the preseason opener, because Bradford has been working 11-on-11 for only a few weeks, as he returns from back-to-back ACL tears.

Kelly also said tight end Zach Ertz will sit out the entire preseason with a nagging "core muscle" problem. He said Ertz should be ready for the season opener Sept. 14 at Atlanta. The Eagles later confirmed that Ertz had surgery, performed by Dr. William Meyers in Philadelphia. Center Jason Kelce said Ertz had a more minor tear than Kelce suffered last season, when Kelce was operated on by Meyers for a sports hernia and missed four games and five weeks. Kelce said it took a few weeks after he came back to really feel right again.

"Obviously, I wanted to be out there. I was preparing to be out there," Bradford said. "This morning (Kelly) kind of sat down and explained it to me. That's up to him. I'll be ready to roll next week, get out there to play against the Ravens."

Bradford said his main objection with not getting the handful of reps the starter will get tomorrow is that "you guys are probably going to keep asking about the knee" until he plays on it. "With each day, I get more comfortable in the offense, I get more comfortable being out there, but as far as a huge difference from this Sunday to next Saturday, I'm not sure how big that is."

Kelly said other participants for the preseason opener against the Colts will be determined after Saturday's practice. Inside linebacker Mychal Kendricks, who has missed the past few practices for reasons that are unclear, said he isn't playing. Kendricks said his impression is that quite a few regulars will sit.

Kelly said the Eagles have not tried to put linebacker Kiko Alonso through the NFL's entire concussion protocols, because they feel no urgency to get him on the field right now. Alonso is in meetings, meaning he has passed Stage 1 of the requirements. Alonso will not play against the Colts.

Kelly said he knew Bradford was disappointed in his decision but "it wasn't a debate." Kelly indicated Bradford will play in the second preseason game, Aug. 22 against Baltimore, which will follow a week of practices with the Ravens.

Bradford said he was indeed disappointed but supports Kelly's decision. Bradford noted that he hasn't missed a single rep since training camp began; clearly, there is no concern that his knee is not OK, just concern that he isn't quite ready to test it in a game.

Kelly said Mark Sanchez will start at QB on Sunday but won't play much, with the bulk of the work going to Matt Barkley and Tim Tebow (who likely are fighting for one roster spot).

"He's been out here just for two weeks; the other guy's got a little better base," Kelly said of Bradford and Sanchez. "There's a fine line" between wanting to get a player ready for the season, and exposing him unnecessarily to injury, Kelly said, citing the ankle injury Washington tight end Niles Paul suffered in his team's preseason opener; the injury will sideline Paul for the season.

Kelly said Meyers, the go-to surgeon for groin/sports hernia-type injuries, thought the Eagles could get Ertz healthy by sitting him now, rather than trying to nurse the injury through the season.

"We just wanted to get it cleaned up," Kelly said.

Meanwhile, after Kelly spoke, the Eagles announced that they had waived/injuured linebacker Brandon Hepburn, who had been a contender for OLB playing time in the wake of Travis Long's season-ending ACL injury, Kelly said Friday that Hepburn was out with an abdominal problem.

Also waived was DE B.J. McBryde, who has a foot issue. The team signed DE Alfy Hill.