The guy meant to run into him, sure - and by run into I meant just give him a little bump - but he didn't meant to injure anyone. Football is a contact sport, but like any competition there is a psychological aspect. He meant to bump to intimidate and irritate the WR. To do so without penalty, it would have to be unintentional so he stared at his defensive teammates. That leg came back pretty quickly too. I don't think it was a cheap shot.
To me, it looks like he didn't see the leg pop out, or he didn't see the player at all - which seems a little unlikely.
Or he meant to kick the WR in the leg.