I wish my league started a flex. But I have him (no Foster), and really like the depth he provides - he's start-able in a pinch as a RB2, and of course should be gold if Foster goes down.
Got offered Freddy Jax for him this week and turned it down. Not sure that was the right move, but think I'd rather hold onto him for a RB in a better situation, or a really good WR2.