Oklahoma defensive tackle Gerald McCoy's announcement on Friday that he will leave school early marks the third Oklahoma underclassman who plans to declare for the NFL draft in April.

McCoy joins quarterback Sam Bradford and tight end Jermaine Gresham. Bradford missed most of the 2009 season with a shoulder separation, and Gresham missed the entire season after injuring his knee in training camp.

Bradford made a formal announcement soon after his surgery was completed. And Oklahoma coach Bob Stoops said earlier this season that Gresham plans to declare for the draft, despite his season-long injury.

Their departures, along with those by Kansas wide receiver Dezmon Briscoe and Oklahoma State wide receiver Dez Bryant, give the Big 12 five of the 10 players who have declared early for the draft through early Monday.

Three other players have decisions that will likely shape how the 2010 season plays out after their intentions are made known.

Texas safety Earl Thomas has said he plans to return to school. He'll have to make announcement after the Longhorns' Jan. 7 Citi BCS National Championship Game against Alabama.

Oklahoma running back DeMarco Murray told Oklahoma reporters last week he's leaning toward "probably returning" for the 2010 season.

Texas A&M defensive end/linebacker Von Miller, who led the nation in sacks while playing the hybrid "Jack" pass-rushing position with the Aggies, has not made a statement if he is returning for his senior season.

With all of their major Big 12 South rivals losing players or potentially losing players to the draft, it appears that Texas Tech might be the biggest beneficiary heading into next season.

These decisions will be critical in how the upcoming season transpires for Big 12 teams. But it already appears that the early additions to the draft should give the Big 12 a good chance to break the conference's record of seven first-round NFL draft picks set last season.