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."

Though the Vikings had more pressing needs on the offensive line in the draft, they refused to pass up the potential Hughes presented with the 30th overall selection out of Central Florida . In addition to seeing extensive time in the secondary, Hughes has taken turns returning kickoffs and punts and also played on coverage units.

With Mackensie Alexander (ankle) out for the opener against San Francisco, Hughes was the slot cornerback in the nickel package and returned an interception of 49ers quarterback Jimmy Garoppolo for a touchdown . He has played capably on the outside, too, starting at left cornerback for Trae Waynes (concussion) last week at Philadelphia. Waynes missed the second half of three other games because of injuries, forcing Hughes into unexpected action in those situations as well.

With Terence Newman now on the coaching staff, undrafted rookie Holton Hill will move up on the depth chart, with Xavier Rhodes, Waynes and Alexander the top three cornerbacks.

"He's got a lot of great attributes, like toughness, and his skillset is really good," Zimmer said. "He's going to come back, and he's going to be great."

Zimmer has often been hard on rookies, particularly for cornerbacks, his position of expertise, but Hughes quickly drew his praise for his attention to detail and willingness to learn in training camp as much as his natural abilities. Alexander, for example, was called out more than once by Zimmer over his first two seasons for being slow to adapt to the responsibilities of the nickel back.

"For a young guy, he was real professional about everything," Zimmer said. "Studied hard, asked good questions, never afraid to ask anything, not afraid to compete."

This is the second straight year the Vikings have lost their top pick to 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.

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