Shannon technically has three seasons of eligibility remaining because his freshman year in 2019-20 didn't count against players after the coronavirus pandemic led to the cancellation of the Big 12 and NCAA tournaments.
Shannon averaged 12.9 points and 4.0 rebounds per game this past season as Texas Tech reached the second round of the NCAA tournament. His overall averages for two seasons are 11.3 points and 4.1 rebounds.
ESPN rates Shannon as 33rd in its latest ranking of this year's draft class.
Shannon is the fourth Texas Tech player in as many years to declare early for the draft. The other three -- Zhaire Smith (2018), Jarrett Culver (2019) and Jahmi'us Ramsey (2020) -- didn't return. Culver was the only one drafted in the top 10.
The decision by Shannon comes soon after Chris Beard left as coach to take over at Texas, his alma mater and Texas Tech's biggest rival. Beard led the Red Raiders to their first NCAA championship game in 2019. Virginia won the title in overtime.
Information from The Associated Press was used in this report.