The Kentucky Wildcats face a tough test in hosting No. 1 Mississippi State this afternoon, and their task got that much tougher with the announcement that star freshman tailback Stanley “Boom” Williams will miss today’s game due to a concussion suffered last week against LSU.

Williams was hit helmet to helmet on a kickoff return in the third quarter of last week’s game, forcing him to miss the remainder of the game and a full week of practice this week as he recovered from the head injury.

The star freshman confirmed he’ll miss today’s game on Twitter this afternoon.

Sophomore Jojo Kemp, junior transfer Braylon Heard and fellow freshman Mikel Horton will all see increased roles out of the backfield in Williams’ absence. Williams is third on the team in rushing behind Kemp and Heard, but he leads the team with a 7.4 yards per carry average in 2014.

Williams will also be missed in Kentucky’s passing game — where he’s earned more than twice as many receiving yards then any other UK tailback — and in the return game, which struggled last week against LSU.