Thomas' name was among the 65 underclassmen listed in a release from the NFL on Thursday.
The Texas City, Texas, native was expected to start for OSU in 2011 but Daytawion Lowe took his place once the NCAA ruled him ineligible. Thomas started 11 games for the Cowboys in 2010, including the final nine. He finished with 63 tackles, five pass breakups, three interceptions, two fumbles forced and one fumble recovery.
Perhaps his most memorable game came in the Cowboys' 2010 victory at Kansas State. Thomas had six tackles, an interception he returned 26 yards for a touchdown, a forced fumble and also downed a punt at the 1-yard line against the Wildcats.
Thomas played in 35 career games for Oklahoma State and finished with 100 tackles. Thomas joins two-time Biletnikoff award winner Justin Blackmon as the only two underclassmen leaving OSU for April's draft.
In addition to the unexpected loss of Thomas, All-American strong safety Markelle Martin wrapped up his senior season and is headed for the draft. That leaves Lowe, Deon Imade, Isaac Maselera and Zack Craig as the Cowboys' returners at safety in 2012, not including any Mike Gundy and his staff should add in recruiting.