Arkansas coach Bobby Petrino said that Mallett suffered a concussion on the hit.
Mallett was taken to the locker room after guiding the No. 12 Razorbacks to a touchdown for a 14-10 lead with 5 minutes left in the first half.
No. 7 Auburn won 65-43 in the crucial Southeastern Conference game.
Sophomore Tyler Wilson took over at quarterback and guided Arkansas to a touchdown.
Mallett was averaging nearly 350 yards passing.
Information from ESPN.com's Chris Low and The Associated Press contributed to this report.