Arkansas defensive coordinator Willy Robinson will not return in 2011.

Arkansas coach Bobby Petrino confirmed the news through a statement Tuesday afternoon, saying Robinson had “resigned” after four seasons on his staff.

“I want to thank Willy Robinson for his role in helping our defense, which he leaves in better shape than when he arrived,” Petrino said in the statement. “I have the utmost respect for Willy Robinson as an individual who wants the best for the young men he coaches. I give Willy credit for his part in the building process the last four years and wish him future success.”

Robinson is the third coach — and coordinator — to leave the Arkansas staff this week.

Offensive coordinator Garrick McGee was named Alabama-Birmingham’s coach on Monday. Special teams coordinator John L. Smith was named Weber State’s coach earlier Tuesday. Petrino has hired his brother, Paul Petrino, as Arkansas’ offensive coordinator/quarterbacks coach.

It’s not clear what Arkansas plans to do with its defense for the Cotton Bowl. Linebackers coach Reggie Johnson served as defensive coordinator during a game in 2009, when Robinson was hospitalized. Defensive tackles coach Bobby Allen and defensive ends coach Steve Caldwell also have experience as defensive coordinators previously in their careers.

— Robbie Neiswanger • Arkansas News Bureau