Arizona State quarterback Sam Leavitt has been ruled out for the No. 21 Sun Devils' game at Utah on Saturday.
Leavitt had been listed as probable Wednesday before being downgraded to doubtful Thursday then out Friday on the Big 12's availability report.
"Sam's been battling something going back to Baylor. He fought through the TCU game," Sun Devils coach Kenny Dillingham told Arizona Sports 98.7 FM on Friday. "Sam does everything he possibly can to come back and play in football games. He's the ultimate competitor.
"This week, it just didn't feel as good as we wanted it to leaving Wednesday's practice," Dillingham added. "I think this is the best thing for him and the future season."
With Leavitt out, backup Jeff Sims is in line to start for Arizona State in Salt Lake City. Sims has started 26 games over his career, including one at Arizona State, two at Nebraska and 23 at Georgia Tech.
Sims started one game last year for the Sun Devils, a 24-14 loss at Cincinnati. He started college in 2020, playing for Georgia Tech in the COVID-19 season.
Leavitt's injury, which was not disclosed, comes in the wake of a bye after Arizona State's 27-24 win over TCU on Sept. 26.
Leavitt is one of the country's most noted quarterbacks, as he led the Sun Devils to a College Football Playoff bid last season. He entered the season as an intriguing NFL prospect with a blend of size, speed and productivity.
A sophomore, Leavitt has thrown for eight touchdowns and 1,039 yards this season, completing 63.1% of his passes. After struggling at Mississippi State in Arizona State's only loss of the season, Leavitt has five touchdown passes and zero interceptions in the three subsequent games.
Leavitt passed for 24 touchdowns and six interceptions last year, including throwing for 222 yards and running for 60 yards against Texas in the CFP.
Arizona State beat Utah 27-19 in Tempe last year, snapping a four-game Utes win streak in the series.
The Associated Press contributed to this report.