Although he possesses an excellent wing span, he is a bit undersized for the 2 at 6'5 1/4" (with shoes) and 180 lbs. He will obviously need to gain some weight and add strength to be able to guard most NBA 2's. If Jeremy moves over to guard the 2, which he does often, I'm not sure Lamb will consistently guard the point position.
While Lamb is known as a good shooter, his 3 pt % in his final year of college was actually worse then JLin's:
Lin - (34.1%)
Lamb - (33.6%)
This is a bit worrisome. His stroke seems pure but his college shooting numbers aren't all that great. We'll have to wait and see on this.
He is pretty athletic and moves well without the ball. I like his mid range game and he can finish strong with his length. This length also gives him the potential to be a good NBA defender as well.
I say he contributes as a Rookie but is at least a year away, probably two, from being a decent starter (15 PER). Also, don't forget any of the young guys (except JLin) are chips that could be traded at anytime.