Vegas just knocked 5 points off the Bears. Nobody will say why.

Reason 1: Geno's clean sheet ends

Geno Smith has thrown 102 passes without an interception and leads the league at 75.5 percent. Lovely. He also threw a league-high 17 picks last season. Regression is a patient animal.

Chicago's defense already has three interceptions, two of them on Monday night against Philadelphia. And Smith will be throwing to a thinner cast: Breece Hall, Adonai Mitchell and Mason Taylor are all out, and tight end Kenyon Sadiq is questionable.

Reason 2: Chicago wins the turnover battle

Here is the hole in the Jets' defense. It is decent at the passer, holding opponents to 6.0 yards an attempt with 8 sacks. But it has zero interceptions on 93 passes and two takeaways all season, both fumble recoveries.

The Bears are plus-3 through three games. A defense that never takes the ball is the one least likely to punish a backup quarterback's ordinary day.

Reason 3: Chicago by four or more

We don't think it matters much. Chicago has scored 89 and allowed 53. The Jets are 64 to 61. That is not a 3.5-point gap.

Five points gone, and a quarterback switch

The line opened at Bears -8.5 and sits at -3.5 on Saturday, the median of nine US sportsbooks. Five points gone. Nobody has said why.

Here's what changed. The Bears are expected to start Tyson Bagent, per NFL Network's Ian Rapoport, though Ben Johnson still won't say it. Asked Friday, he told reporters: "We'll find out on Sunday." It's Bagent's first start in 1,059 days. Case Keenum, who went 24 of 34 for 247 yards and two touchdowns last week, backs him up. Johnson had dropped the hint: "there was a reason why Tyson [Bagent] ended training camp as our No. 2 quarterback."

The protection changed too. Left tackle Braxton Jones went on injured reserve; Theo Benedet starts. Caleb Williams is ruled out a second week with a Grade 2 hamstring strain.

The case against us

Chicago's pass defense is generous: 7.8 yards an attempt, and Bryce Young threw for 361 against it. If Smith keeps it clean, reasons 1 and 2 go down together.

And the Bears' secondary is short. Cornerback Kyler Gordon is out and Cam Lewis doubtful, with linebacker Noah Sewell and lineman Shemar Turner also out, and safety Anthony Johnson Jr. went on injured reserve Saturday. Fewer hands to catch the interception reason 1 needs.

Turnovers also cut both ways. The Bears were minus-2 in their loss to Minnesota. And Smith carved Detroit for 321 yards and three touchdowns last week.