Chiefs quarterback Patrick Mahomes has undergone surgery in Dallas to repair a torn ACL in his left knee. The team said in a statement that Mahomes had the operation Monday night and will begin the long rehabilitation process immediately. The procedure was performed by Dr. Dan Cooper, a highly regarded orthopedist and the team physician of the Dallas Cowboys. Mahomes tore the ligament when he was spun to the ground in Sunday's loss to the Los Angeles Chargers. Most players are able to return to the field in six to 12 months after an ACL repair, which means Mahomes should be back at some point next season.