Osby, a 6-foot-8 senior, is the first Sooners player to make the All-Big 12 first team since Blake Griffin in 2009. He was the leading scorer
(15.7) and rebounder (6.9) for Oklahoma (20-10) this season.
He left Starkville in 2010 after two seasons in which he averaged about 4.2 points and 2.5 rebounds per game.
Last season, he averaged 12.9 points and 7.3 rebounds.
He has started 60 of 61 games over the past two seasons.
The Big 12 opens its conference tournament today in Kansas City. The Sooners play Iowa State on Thursday.