The three players I think have the most likely chance of not being on the team sans Foles are Vinny Curry, Torrey Smith and Brent Celek.
Curry has been good but we have depth at his position and we still have Brandon Graham's one year contract to figure out.
I like the guy but Torrey Smith has been too inconsistent in a year where we've had good WR play. I think that's about 10 mil between the two of them saved if they were cut/traded/etc.
Brent Celek is a guy who absolutely needs to retire as an Eagles so hopefully he's willing to take a pay cut/restructure if he has any aspirations to play next year. I expect him to play for as long as they want to pay him something but I could see him retiring this year. I'm almost positive that he'll retire if he's not on the Eagles anymore.
But yea, could be tough to actually keep Foles even if his contract stays the same. I hope they do though. If someone can make it happen or make me happy about a Foles trade it's Howie Roseman.