There are two ways to say that:
Sapp says Wentz got 4000 yards and along the way lost his WR1, WR2, WR3, TE, RB1 and RB2.
I could say Wentz finished 9th in passing yardage even though his 3 WRs missed 25 games, his TE missed 1 and two of his RBs missed 22 games.
The Eagles had more injuries than most but the only guys who missed more than half the season were Corey Clement and a 33 year old Desean Jackson who wasn't on their team last year and is four years removed from his last 1000 yard season. Its not like Wentz was playing with his practice squad for the entire year.