[Kansas City.com] Summer vacation officially started late Sunday with the end of minicamp, but the mood wasn’t exactly festive. The Chiefs are now looking for a starting cornerback.

Head coach Dick Vermeil said cornerback Julian Battle is out for the season because of a torn Achilles’ tendon. Battle, who had been elevated to the first team earlier this month, suffered the injury in Saturday’s workout and will undergo surgery on his left heel.

Battle’s injury leaves a big hole, which deepens with the uncertainty of Eric Warfield’s status. Warfield, the Chiefs’ best cornerback in 2004, was demoted to the second team in anticipation of a suspension from the NFL for violating the league’s substance-abuse policy.

He could miss as many as four games, and it could come at the start of the season, when the Chiefs open with the New York Jets, Oakland Raiders and Denver Broncos.