EAGAN, Minn. (AP) — Minnesota Vikings cornerback Mike Hughes has a torn anterior cruciate ligament in his left knee, ending a promising rookie season after six games.

Coach Mike Zimmer confirmed the diagnosis on Monday, after Hughes was hurt in the fourth quarter of Minnesota’s 27-17 win over Arizona on Sunday. Hughes was covering Cardinals wide receiver Larry Fitzgerald in the slot, when he tripped during a brief tangle of feet with Fitzgerald as he angled off a post route about 10 yards deep. As Hughes tried to keep his balance, his left leg bent sideways as he tumbled in pain to the turf while grabbing his knee.

“This has always been a deal where, if somebody gets hurt, everybody else has to continue to step up and play,” Zimmer said. “We feel bad about Mike, because I think Mike is going to be a really good football player. But we’ve got other guys here, and we expect them to come in and do a good job.”

an ACL injury in October. Running back Dalvin Cook went down in the fourth game last season, and Hughes was knocked out of the sixth game this time.