Utah ran a reverse, and Irabor was the only player around to make a tackle. He dove headfirst, leading with his helmet to take out the Utes player at the legs.
Irabor stayed down in what appeared to be a preventative measure. After he stood up, it was clear that he was in pain. It could be a minor issue, such as a bad stinger. Neck injuries, even small ones, have a way of manifesting themselves in the future.
The ASU secondary is already depleted, and losing Irabor for even a few possessions could be a bad thing. Fortunately, on the next play of the game, Irabor's replacement, Alden Darby, intercepted a Jon Hays pass to give the Devils the ball at their own 15 yard line.
For more on the Devils, check out House of Sparky.