You'd think so wouldn't you given the way people talk about him.
In reality he's only managed 15 in 3 PL seasons out of 8 which is not exactly suggestive of it being guaranteed. Also, in spite of his "economical" work rate, he's spent a fair bit of time out injured during his time here which I would interpret as him becoming (at least slightly) more injury prone, making the idea of him playing all 38 games pretty unlikely IMO.
That said, I'd still rather we sold him to Palace than Toon or Fulham, just to be safe.