Auburn head coach Tommy Tuberville made that announcement on Friday following his team's second practice for the Cotton Bowl game.
Sears missed six games in the last two seasons because of a DUI arrest last November. Blackmon, who also had an alcohol-related arrest, missed the first six games of the season. Both will miss the Cotton Bowl game because what Tuberville called a violation of team rules.
Lester, a sophomore tailback, will also not make the trip to Dallas
Sears is a senior and won't have the opportunity to play another game for the Tigers. Tuberville said the other two players are "indefinitely" suspended and didn't rule out they could return for spring practice.
Sears had 13 tackles in seven games this season as a back-up middle linebacker and he finishes his career with 83 tackles and 7.5 tackles for a loss in 41 games. Blackmon and Lester are expected to rejoin the team for spring training.
Blackmon was a blue-chip prospect out of LaGrange High School but has only played in six games at Auburn.
Blackmon had an immediate impact for the Auburn defense after his long awaited return to action against Florida. He played in just six games during his freshman season and had 18 tackles, 2.5 tackles for a loss and three fumble recoveries.
Lester rushed for 510 yards and nine touchdowns and added 87 yards receiving with another score in a back-up role to the oft-injured Kenny Irons.
Lester must also be replaced as a kick returner alongside Tristan Davis. He is the Tigers' second leading scorer behind kicker John Vaughn and is the only Tiger to score more than four touchdowns this season.