South Dakota State junior quarterback Thomas year starter, according to a published report.
The Argus Leader of Sioux Falls reported Tuesday that South Dakota State (1-2) will likely start redshirt freshman Austin Sumner in the Jackrabbits' Missouri Valley Conference opener at Illinois State on Saturday.
Jackrabbits coach John Stiegelmeier was said to miffed by a play late in the first half of last Saturday's game at Cal Poly when O'Brien slid feet-first at the Mustangs' 1-yard line rather than putting his head down to try to get into the end zone. The clock ran out to end the half without the Jackrabbits scoring any points on the possession.
O'Brien threw for a career-high 376 yards, but had two interceptions returned for touchdowns.
He helped lead South Dakota State to an FCS playoff berth in 2009, but struggled as a sophomore last season when the Jackrabbits went 5-6.