A 6-foot-9 big man, Groves earned Big Sky Conference player of the year honors after averaging 17.2 points and 8.0 rebounds this past season. He shot 34.9% from 3-point range and 56% from the field. He tallied nine double-doubles, including 14 points and 14 boards in the Big Sky title game against Montana State.
Groves boosted his stock dramatically in the NCAA tournament, scoring 35 points and making five 3-pointers in a first-round loss to Kansas. Eastern Washington was up double digits on Kansas in the second half before the Jayhawks came back.
Less than one week later, Portland hired Eagles coach Shantay Legans, and Groves decided to enter the transfer portal.
Groves is new Oklahoma coach Porter Moser's first major addition since arriving in Norman to replace Lon Kruger, who retired following the season. Moser needed a replacement for forward Brady Manek, who transferred to North Carolina last week.
Tanner's brother, Jacob Groves, also entered the transfer portal last month. It's unclear whether he will follow his brother from Eastern Washington to Oklahoma.