NFL

Coaches for Jets, Colts have little in common

INDIANAPOLIS — Rex Ryan has a twin brother on the sidelines in Cleveland, but the Jets head coach most certainly does not possess a twin personality on the sidelines in Indianapolis.

In fact, there might not be a coach on the planet more diametrically opposite in personality and coaching style than the Colts’ Jim Caldwell.

So incredibly stoic during games that it seems as if he never blinks, Caldwell is the definition of the anti-Rex as he prepares to take on Ryan’s team here tonight in an AFC wild-card matchup.

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Foot-fetish videos? You’re more likely to see a Bible sermon on YouTube from the religious, soft-spoken Caldwell.

“Night and day, oil and water,” Colts Pro Bowl defensive end Robert Mathis said with a wry smile this week when asked to compare Caldwell and Ryan.

Not many NFL coaches are in Ryan’s class when it comes to boisterous personalities, but Caldwell appears to go out of his way to take the opposite tack. The first black coach in the history of the ACC when he took over Wake Forest in 1993, Caldwell whispers clichéd and milquetoast comments to the media, rarely raises his voice in public and barely moves on the sidelines during games.

And the second-year successor to Tony Dungy doesn’t apologize for any of it.

“You have different styles and things of that nature, and what do they say, ‘There are several ways to skin a cat?’ ” Caldwell said this week. “I choose to do it the way that I do it, do it my way and know what I am judged by.”

If Caldwell comes off as wooden as a toothpick to outsiders, that doesn’t bother his players.

“Every coach goes about it in a different way,” Colts running back Joseph Addai said. “We might go about it a different way, another team does it a different way. Everybody has a different concept.”

Added Mathis: “Coach Caldwell is a no-nonsense kind of guy. He is not going to give you a whole lot of bulletin board material, per se.”

Considering the Colts reached the Super Bowl last year and overcame a mountain of injuries this season to make the playoffs for the ninth year in a row, that stolid style has been successful for Caldwell in the NFL so far.

But a closer look at the mildly surprising choice to succeed Dungy after the 2008 season indicates the jury is still firmly out on Indy’s 55-year-old leader.

First off, Caldwell has the luxury of four-time NFL MVP Peyton Manning under center — a factor that would make any coach look good. And the presence of one of the league’s most feared pass rushers in Dwight Freeney and top receivers in Reggie Wayne doesn’t hurt, either.

Caldwell also came under fire both locally and nationally last year when he passed up a shot at a perfect regular season and tanked the final two games (including a home date with the Jets) after a 14-0 start because he wanted to rest his starters.

That strategy — the opposite of what Tom Coughlin did in 2007 en route to a Lombardi Trophy — appeared to haunt Caldwell in Super Bowl XLIV, when the heavily favored Colts endured a 31-17 throttling by the upstart Saints.

That stinging defeat was followed by this season’s slump to 10-6 that marked the Colts’ worst record since 2002. A loss tonight would be just their second wild-card exit in the past eight years.

Caldwell’s defenders point to the Colts overcoming an unthinkable amount of injuries in 2010 (17 players finished the year on injured reserve), but Manning catching fire during a four-game win streak to end the season arguably played the biggest role.

Is Caldwell, as some league insiders insist, just a caretaker blessed with a Hall of Fame quarterback?

Or is he a smart, savvy coach ready to oversee the Colts’ second Super Bowl bowl title since moving to Indiana in 1984?

Whichever proves to be the case, one thing is for sure: Caldwell will never have to worry about comparisons with tonight’s coaching opponent.

“I learned this a long time ago: Everybody has their own personality, and thus they have to live by it,” Caldwell said.

bhubbuch@nypost.com