IRVING, Texas - Jerry Jones fired Rob Ryan last season because his former defensive coordinator’s scheme was too gimmicky.

Now the Dallas owner says gimmicks are what the Cowboys need with a defense that may go down as the worst in franchise history.

Monte Kiffin’s new 4-3 alignment and the players trying to run it simply couldn’t stop backup quarterback Josh McCown in Chicago’s 45-28 victory over Dallas on Monday night. McCown had four touchdown passes and a rushing touchdown and the Bears scored on their first eight possessions before McCown took a knee to end the game.

“We’ve got to look for ways to come up with whatever gimmick, whatever plan that we can to get us the ball and get some turnovers and get some possessions,” Jones said. “Did we ever stop them one time tonight? They scored every time. That says it all.”

Jones offered support for Kiffin on his radio show Tuesday, but the mounting evidence suggests the owner’s biggest change of the off season isn’t working.

Dallas became the fifth team since 1991 to allow an opponent to score on the first eight possessions, according to STATS. The previous three teams won five games combined.

Somehow, the Cowboys (7-6) still control their playoff fate with Green Bay visiting Sunday, although they are a full game behind Philadelphia (8-5) in the NFC East for the first time this season.

“It feels like you’ve got to win out is what it feels like,” quarterback Tony Romo said. “It’s felt like that for a few weeks.”

With five games of at least 490 yards allowed, the Cowboys have tied the 1965 Houston Oilers and 1950 Baltimore Colts for the most since 1950. They have set NFL records by allowing four quarterbacks to pass for more than 400 yards and surrendering 40 first downs to New Orleans in another humiliating loss, 49-17 a month ago.

In a twisted way, Dallas is used to bouncing back from horrid defensive games.

The Cowboys beat Washington after giving up 517 yards in a 51-48 loss to Peyton Manning and Denver, and rallied past Minnesota after Detroit put up 623 yards. They produced a clutch winning drive at the New York Giants after having their bye week to ponder Drew Brees and the Saints going for 625 yards.

Now Dallas has a short week to get ready for the Packers, who could have Aaron Rodgers back. He has missed six games with a left collarbone injury.

“We’ve had a couple of these games this year,” Coach Jason Garrett said on his radio show Tuesday. “Whether it’s what we’re doing with our scheme, our personnel, what we’re asking guys to do, we’ve just got to make sure we get that done and we’ve got to get that done quickly.”

Healthy or not, the Cowboys couldn’t stop the Bears. Chicago scored touchdowns on its first two drives with Sean Lee back at middle linebacker after missing two games with a hamstring issue. He went out later with a neck injury, and his status is uncertain for the Packers game.

Health hasn’t always been a gauge for the Cowboys.

Dallas won both games without Lee and shut down one of the league’s best running games in a victory over Oakland. Philadelphia’s only game without a touchdown was a 17-3 loss to the Cowboys when Dallas was missing defensive end DeMarcus Ware.

So the Dallas defense is hard to figure, but there is one brutal bottom line. With three games left, the Cowboys are just 138 yards shy of the team record of 5,549 yards allowed last season.

“The system’s there,” Lee said. “It has everything to do with just executing properly. Gave up way too many big plays. Didn’t get off the field on third down. Basic stuff. Didn’t do it.”

MONDAY’S GAME Chicago 45, Dallas 28

THURSDAY’S GAME All times Central San Diego at Denver, 7:25 p.m.

SUNDAY’S GAMES Philadelphia at Minnesota, noon Washington at Atlanta, noon San Francisco at Tampa Bay, noon Seattle at NY Giants, noon Chicago at Cleveland, noon

Houston at Indianapolis, noon Buffalo at Jacksonville, noon New England at Miami, noon Kansas City at Oakland, 3:05 p.m.

NY Jets at Carolina, 3:05 p.m.

Arizona at Tennessee, 3:25 p.m.

New Orleans at St. Louis, 3:25 p.m.

Green Bay at Dallas, 3:25 p.m.

Cincinnati at Pittsburgh, 7:30 p.m.

MONDAY, DEC. 16 Baltimore at Detroit, 7:40 p.m.

Sports, Pages 24 on 12/11/2013