It's not what you think should happen, it's what you think the coaching staff will do.
Deangelo brings nothing to the table, Fozzy would be more effective in the screen game.
But you're right, if Deangelo can play Rivera forsure gives him some playing time. It's things like this that should still cost Rivera his job.
I said the same thing when Amini went down and how it was a blessing in disguise because Rivera is unable to make these kind of necessary changes