Philly has to go in a new direction. It's the perfect time, AJ feeley is not playing great, but well enough to keep the seat warm for Kevin Cobb(sp?), and that's what they need right now a solid back-up who is inexpensive, that can drive the bus until the kid is ready to take over. Even if they do keep Donavan through next year, his job will always be in jeoperdy b/c of the high draft pick they used on Cobb. Besides McNabb has a huge contract, and cap number. Not to mention we are in the middle of the annual Donavan Mcnabb multiple game injury.
It would also be the right thing for Mcnabb, who has been a solid QB for years. There are at least 20 teams out there that would love to have him, but for some reason Philly fans hate the poor guy. Right off the top of my head, Minn, Chi, SF, and Baltimore all need QB's BADLY. Also there is a longshot of SD or NYG needing a new guy. The big issue is that Donavan not only has a huge contract, he will likely want a new long term huge contract with his new team.
IMO what it comes down to is what Donavan thinks he's worth vs. the team's perception of his ability to stay on the field for an entire season.