Sumlin issued a statement Tuesday afternoon detailing his decision and apologizing to the West Virginia players and coach Dana Holgorsen.
"Upon returning to College Station last night, I had the opportunity to gather information and watch clips of one of our student assistant coaches initiating physical contact on two separate occasions with a West Virginia player," Sumlin said. "I am extremely disappointed and embarrassed, as his behavior reflected poorly on our program.
"On behalf of the Texas A&M football program, I want to apologize to Daryl Worley and to Andrew Buie as well as to Coach Holgorsen and the West Virginia family for the inexcusable actions of the student assistant. I removed him from the sideline at halftime of yesterday's game after being informed of the incidents and, after further review, have permanently dismissed him from our football program."
Cameras showed Richardson striking West Virginia players who ventured out of bounds during Monday's first half on two separate occasions. He used his elbow to strike Worley, a cornerback, in the back of the head and shoved Buie, a running back, in another incident.
Richardson took to Twitter earlier Tuesday to express remorse for his behavior.
On Monday night, Worley tweeted that he would "see [Richardson] again in life," but on Tuesday had softened his stance and spoke of both him and Richardson needing to take the high road.A class of 2012 signee out of DeSoto (Texas) High, Richardson played linebacker as a true freshman for Texas A&M before suffering a career-ending neck injury in a Nov. 17, 2012, win over Sam Houston State. He had surgery shortly thereafter and has served as a student assistant coach for the Aggies since his playing days concluded.
Sumlin also apologized to Texas A&M fans in his statement for Richardson's actions.
"I also want to apologize to the Aggie faithful, as they deserve a program to be proud of, not only in our play, but in the integrity and respect we show on and off the field," Sumlin said. "This student assistant coach's actions are not representative of our program."
Texas A&M Staff Member Gets Physical With WVU Players
On two separate plays in the second quarter, Texas A&M student assistant Mike Richardson struck two different West Virginia players.