The announcement confirms fears following Saturday's win against Arizona State in which Kuithe, the team leader in receptions (19), left the game in the first half with an apparent knee injury.
Kuithe was a second-team All-Pac-12 selection last season when he caught 50 passes for 611 yards with six touchdowns. In parts of five seasons, he has 148 receptions for 1,882 yards and 16 scores.
Whittingham told reporters the injury is "a big blow for our offense." Kuithe qualifies for a redshirt season and could return to the team in 2023.
The No. 12-ranked Utes (3-1, 1-0 Pac-12) host Oregon State on Saturday.