Kessler, who started the Trojans' first two games, has been battling Max Wittek for the starting job since fall camp, and USC coach Lane Kiffin had been unwilling to name a full-time starting quarterback until this week. Kiffin met with both quarterbacks and the team before the school announced the decision.
Both quarterbacks struggled in Saturday's 10-7 loss to Washington State. Kessler started the game and completed 8 of 13 passes for 41 yards and one interception in the first half, and Wittek completed 3 of 8 passes for 13 yards and one interception in the second half.
The longest completion for either quarterback was 8 yards.
USC's 54 passing yards were its fewest in a game since 1998.
"I've never heard of stats like we had today," Kiffin said. "That's very discouraging and obviously that falls on me."
Kiffin did not meet with the media on Monday after making the decision but the school released a Youtube video of him addressing his choice.
"I'm not going to, for the protection of the guys, get into this guy did this and this guy didn't do that," Kiffin said in the video. "We made the decision to go with Cody and we're excited about how well he's going to play Saturday."
Although Kiffin announced his decision to the team on Monday, he met with both quarterbacks to inform them of his decision Sunday.
"I spent a lot more time when these things happen with the guy that doesn't get it," Kiffin said. "Obviously the one guy's going to be excited. I spent some time last night with Max, making sure that he's ready to go and that he's in a good place. We don't expect him to agree with us. He's very competitive like all the guys we recruit. They all should think they should be the starter."
Kiffin said he had hope that having one starting quarterback would help stabilize an offense that has struggled to move the ball the first two weeks of the season, ranking 112th in the nation in passing yards and 99th in points scored.
"I think it will help us in general just knowing it's one right now," Kiffin said. "We can game plan around that and now we can get off of the 50-50 reps and get back to Cody getting the majority of the reps."