I don't think he'll be anything elite, but he is steady handed, tough, and has the mindset of being willing to take on any role to help the offense move the ball and score. Don't be put off by his combine numbers, he played the entire college season with a sports hernia (and still caught 71 for 964 yards and 7 TDs) and then had surgery after the season.
EDIT: If I was going to put a cap on where I think he could get, I'd say that what reasonable people's expectations of Zay were last year isn't outside the realm of possibility.