A university spokesperson confirmed Kendall's entry to the Associated Press on Friday.
Kendall, who will be a fourth-year junior, is in line to take over as the starting quarterback for the Sooners in 2019 after spending the past three seasons backing up Heisman Trophy winners Baker Mayfield and Kyler Murray.
While Murray is exploring entering the NFL draft, blue-chip quarterback recruit Spencer Rattler is not joining the Sooners until the summer.
Alabama quarterback Jalen Hurts, who himself has entered the transfer portal, could be an option for Oklahoma, regardless of Kendall's decision. Sources have told ESPN there is mutual interest between the two.