Lions’ Kelvin Sheppard calls for changes as defense ranks last in yards allowed

Detroit Lions defensive coordinator Kelvin Sheppard identified trust and assignment problems in the back seven as he outlined potential changes before Sunday’s game against the Arizona Cardinals.

Detroit allows a league-high 423.8 yards per game. Sheppard said Thursday that the defense’s first four games had fallen well short of his training camp expectations, according to the Lions’ official report.

He praised the defensive line but said the linebackers and secondary had failed to complement it. Sheppard explained that defenders were peeking into a teammate’s gap and leaving their own assignment uncovered.

Rookie defensive back Keith Abney II could receive a larger role against Arizona. Sheppard said Abney can play outside corner, nickel or safety. Moving him to safety could allow Christian Izien to spend more time at nickel.

Detroit will again be without Brian Branch. The defensive back practiced on a limited basis this week, but the team ruled him out Friday with an Achilles injury. Cornerback Rock Ya-Sin was also ruled out with a hamstring injury for Sunday, October 11.