In 9 games Sanchez had 15 TDs(1 rushing), 11 ints, and 3 lost fumbles.
In 8 games Foles had 13 TDs 10 ints and 3 lost fumbles.
Maybe i'm missing something but it doesn't appear that Sanchez was worse as you say.
Look, i'm not saying I want Sanchez on the Bills, i'm saying there wasn't a drop off if any from how Foles was performing to what Sanchez did this year. Maybe the Eagles agree with that and resign Sanchez and dangle Foles for trade, as they also have Matt Barkley waiting in the wings. If so, I hope Whaley jumps all over that. Wishful thinking.