The do-everything guard from Mesa, Arizona, joined teammate Both Gach among the 205 players on the league's most recent early-entry draft list.
Players have until June 3 to withdraw from the June 25 draft.
The 6-foot-6 Allen earned second-team All-Pac-12 honors from The Associated Press after averaging 17.3 points, 7.3 rebounds and 3.0 assists for the Utes in 2019-20. He was twice named Pac-12 player of the week, and he shot 58% from the floor, including 57% from 3-point range.
Allen scored 12.2 points per game and shot 57% in 29 games as a freshman.
Gach, a sophomore guard, declared for the draft in early April.