PITTSBURGH — For the New York Jets, the 45-3 loss to the New England Patriots was humiliating. The 10-6 defeat to the Miami Dolphins was humbling.

Quarterback Mark Sanchez couldn’t handle the pass rush or, it seemed, the pressure, and coach Rex Ryan thought about replacing him. The offense didn’t score a touchdown in either game.

“It’s been ugly,” wide receiver Santonio Holmes said.

All of a sudden, the Jets (9-4) are being reminded about their collapse of 2008, when they started 8-3 before losing five straight and missing the playoffs.

Guess what: The Jets might not have seen the worst of it.

The Jets are trudging off to Pittsburgh, where the three rivers are freezing over and the Steelers’ defense is toughening up as January draws near. The Steelers (10-3) held the last two Heinz Field visitors, the Raiders and Bengals, to one touchdown between them, and the Bengals to a mere 190 yards of offense.

“I am concerned,” Ryan said. “The fact that we have to go up against Pittsburgh doesn’t help matters. Really, what I tell our team about them is this will be the best defense we face all year.”

No, there are far friendlier venues for a team that needs to get well in a hurry. Think James Harrison and James Farrior, Troy Polamalu and LaMarr Woodley can’t wait to get their hands Sunday on a confidence-shaken young quarterback, or the passes he throws? Polamalu himself has four interceptions in four games.

“I have seen a lot of guys come down with Pittsburgh flu,” said Ryan, the former Ravens defensive coordinator. “All of a sudden a guy won’t play in the game, saying, ‘Ahh, I’m just not right.’ I’ve seen it happen because they don’t want to face Pittsburgh.”

There’s also this: The Jets are 0-7 in Pittsburgh. Since the 1970 NFL merger, only two other teams have gone winless in more games in an opposing city; the Lions are 0-15 at Washington and the Texans are 0-9 at Indianapolis.

The Steelers can clinch their seventh playoff spot in 10 years by winning their fifth in a row, but all’s not well in the ‘Burgh.

The offense didn’t get into the end zone against the woeful Bengals (2-11). The only touchdown in Baltimore came when the defense gave the offense the ball at the Ravens 9-yard line. The beaten-up and much-reconfigured offensive line is performing better than only two lines in the league, according to data compiled by STATS, LLC. Penalties are piling up like the snow that drapes every Pittsburgher’s front lawn, with 420 yards of infractions the last four games alone.

Ben Roethlisberger, limping on a battered foot and recovering from a broken nose, has been sacked 12 times in three games. Rashard Mendenhall has one 100-yard game in 10 weeks. And the Steelers are about to go against a defense that, at least statistically, is superior even to their own.

Maybe that Pittsburgh flu is going around. Sunday’s forecast: Temperatures in the lows 20s, and scores below even that.

B-r-r-r-r.

“It’s a huge challenge,” said Roethlisberger, whose ability to bounce off defenders and keep a play going has been the offense’s best asset of late. “Obviously it’s no secret we’re not playing as well as we can. But we’re winning, and that’s what‘s important. We’ve had a lot of help from the defense.”

An offense that hasn’t generated a touchdown drive of its own in 11 quarters now must go against the NFL’s top pass defender in Jets cornerback Darrelle Revis, who is bothered by a hamstring problem. Pittsburgh’s Mike Wallace, who averages more than 20 yards per catch, takes that as a personal challenge.

“I just feel like I’m one of the best in the game and feel like he’s the best, so we’ll see,” Wallace said.

Another receiver has something to prove, too. This will be Holmes’ first game in Pittsburgh since the Steelers cast off the 2009 Super Bowl MVP in April, getting only a fifth-round draft pick in return. Holmes was let go during a trouble-filled offseason in which he was suspended four games for violating the NFL’s substance abuse policy.

“I put all that stuff in the past back in April,” Holmes said. “I was very upset at the time but, as far as right now, I don’t care about anything that goes on at the Steelers’ facility.”

The question is how much Sanchez (16 touchdown passes, 12 interceptions) can do by himself against a defense that has virtually eliminated the run, holding opponents to an average of a league-low 60.1 yards per game. The Jets ran for 66 yards against Miami, which won despite gaining only 131 yards, 30 passing, and turning the ball over three times.