South Carolina coach Steve Spurrier said Shaw missed Monday's practice and was unlikely to work out Tuesday as he recovers from the virus. He is questionable for Saturday's game against Mississippi State.
Shaw also was coming off a sprained knee when he entered the game against the Missouri in the third quarter and rallied the No. 14 Gamecocks (6-2, 4-2 SEC) from a 17-point deficit to a 27-24 double-overtime victory.
Shaw threw for 201 yards and three touchdowns, earning the SEC's offensive player of the week honors.
Spurrier says backup Dylan Thompson would start against Mississippi State (4-3, 1-2) if Shaw can't play.