This was a kickoff. Therefore he doesn't have to wait on him to catch the ball. According to the targeting rule, you can't initiate contact with the crown of the head, which he did. It should have been a penalty and ejection according to my interpretation of the the rule.
Ugh, sure?
http://www.dfoa.com/attachments/article/69/2013-14_Football_Rule_Book.pdf
Rule 6, Section 4. "A player of the receiving team within the boundary lines attempting to catch a kick, and so located that he could have caught a free
kick or a scrimmage kick that is beyond the neutral zone, must be given an
unimpeded opportunity to catch the kick."
b. It is an interference foul if, before the receiver touches the ball, a Team
A player enters the area defined by the width of the receiver’s shoulders
and extending one yard in front of him.
When in question it is a foul.
It is an interference foul if the kicking team contacts the potential receiver
before, or simultaneous to, his first touching the ball.
When in question, it is an interference foul.
g. Contact by Team A involving a targeting foul (Rules 9-1-3 and 9-1-4) or other
personal foul that interferes with the receiver’s opportunity to catch a kick
may be ruled either as interference or as a targeting or personal foul. The
15-yard penalty is enforced at the spot where the dead ball belongs to Team
B or at the spot of the foul, at the option of Team B.