FLORHAM PARK, N.J. -- The New York Jets are clinging to the "Next Man Up" philosophy in their secondary -- except they're running out of men.

Backup free safety Doug Middleton, starting for the injured Marcus Maye (broken thumb), will be out for the remainder of the season after tearing a pectoral muscle Sunday during a 37-17 loss to the Minnesota Vikings.

Before the Middleton injury, the Jets were down three of their top five defensive backs: Maye (three games missed), cornerback Trumaine Johnson (three games with a quadriceps injury) and nickelback Buster Skrine (two games with a concussion).

The good news for the Jets is they're not season-ending injuries.

Coach Todd Bowles, speaking Monday to reporters, said Middleton still was undergoing tests, but they feared a tear. A source later confirmed the initial diagnosis was a tear but that Middleton was seeking a second opinion.

It's a tough break for Middleton, who missed last season after tearing his other pectoral muscle in the first preseason game. He made the team in 2016 as a rookie free agent, but has battled injuries the entire time.

When Maye wasn't ready to start the season because of a foot injury, the Jets turned to Middleton, who started the first three games. He returned to a backup role until Maye broke his thumb in Week 6, and Middleton went back to the starting lineup.

The injuries are taking a toll. In the last four games, the Jets have allowed 1,307 passing yards. On Sunday, they face Mitchell Trubisky and the Chicago Bears (3-3) on the road.

Until Maye returns, which should be in two or three weeks, the Jets are planning to use career backup Terrence Brooks at free safety. Rontez Miles, who has recovered from knee surgery, is eligible to come off the physically unable to perform list. He could start practicing this week.

The offense hasn't been immune to injuries, either. Bowles said he's awaiting test results for running back Bilal Powell, who injured his neck in the second quarter and didn't return. Center Spencer Long, battling a middle-finger injury that has caused a handful of errant shotgun snaps, suffered another undisclosed injury late in Sunday's game. His status for this week is up in the air.

The New York Daily News first reported Middleton's injury.