means the receiver had to wait an extra second to catch the ball. The defender saw who the intended receiver was and had already started running over to make the tackle, but if the ball wasn’t tipped the receiver would not have been defenseless by the time the defender dropped the hit.
It’s just hard for a defender to adjust his timing like that, especially when he may not have even noticed that the ball was tipped.
Though I guess he still shouldn’t lead with his helmet.