Slovis was knocked out of the San Diego County Credit Union Holiday Bowl in the third quarter with what coach Clay Helton said was a possible sprain.
The No. 22 Trojans fell apart after Slovis left, losing 49-24 to No. 16 Iowa and snapping their three-game winning streak.
Slovis was hurt on a sack and was replaced by Matt Fink.
"I mean, nothing really changed," USC receiver Michael Pittman Jr. said. "It's just we kind of got shocked because our starting quarterback had gotten out, then it kind of deflected our, like, flow. Just one thing led to another. That's what happened."
Slovis left the game after completing 22 of 30 passes for 260 yards and two touchdowns.
Slovis took over as the Trojans' starting quarterback after JT Daniels suffered a season-ending knee injury in the season opener. He threw for 3,242 yards and 28 touchdowns against nine interceptions in the regular season.
The Associated Press contributed to this report.