What is holding Zach Ertz back right now is the same thing that holds back a lot of young tight ends: his blocking ability.
In the Eagles' first four games, Ertz played 64.5 percent of the offensive snaps. In the last two against the Rams and Giants, only 40.9 percent.
Ertz was just a part of the problem with the run game. A much bigger part was the three missing starters up front. But when your offensive line is struggling, other shortcomings become magnified.
Reducing Ertz' snaps wasn't an easy thing to do, given his ability as a pass-catcher. But Chip Kelly thought it was critical to do whatever it took to get McCoy going.
Ertz has a terrific series of matchups down the stretch, but his snaps have dropped from the 60-75% range to the 40-45% range. The Eagles do play up tempo, so there are a lot of snaps to go around. Ertz should stay in the low-end TE1 discussion, but he doesn't have major upside as a part-time player.