"Obviously, I am disappointed because you never think this could happen to you," Grothe said in a statement released by the school. "It's a team game and I am still going to be very involved with my teammates and the coaches. I am going to do everything I can to help the Bulls continue to win."
Grothe had started 41 straight games for the Bulls (3-0), who play at No. 18 Florida State this week. He became the Big East's career leader in total offense with 10,875 yards in Week 2 at Western Kentucky. He had 121 rushing yards and 512 passing yards this season.
"Matt's a franchise guy and an even better human being," South Florida coach Jim Leavitt said in a statement. "We all know that. What he's done in college football is extraordinary. He has been one of the greatest names out there. We all know that and our entire program feels bad for him. Matt is a special, special guy."
Redshirt freshmen B.J. Daniels, who finished the Charleston Southern game, and Evan Landi will now have to take over.
Blogger Brian Bennett covers the Big East for ESPN.com.