Jim Leyland: “I will wear these underwear until we lose.” (Charles Rex Arbogast/AP)

Had they kept their 12-game winning streak going a day or two longer, they would have locked up the AL Central with two full weeks left in the season.

But at least one Tigers fan is probably glad the Athletics snapped the streak in Thursday’s 6-1 win in Oakland forcing Detroit to try again Friday. That fan: manager Jim Leyland’s wife Katie.

You see Leyland, like many in Major League Baseball, is superstitious. And when the Tigers are winning, he feels the need to keep everything constant, from what he eats, to what he wears — all the way down to his undies.

The Tigers’ streak began Sept. 2 against the White Sox and ended 13 days later in Oakland, during which Leyland never once changed — or washed — his underwear.

“I will wear these underwear until we lose,” Leyland said after the Tigers extended their streak to 12 Wednesday in Chicago. “I can tell you that right now. And they will not be washed. And I don’t give a (expletive) who knows it.”

Leyland also said he’d been smoking a cigar every day and was wearing the same hole-covered baseball socks. The 12-game streak was the longest for the Tigers since Hank Greenberg and Charlie Gehringer ’s 1934 team won 14 straight en route to the World Series.

With the streak over, here’s hoping Katie Leyland takes the opportunity to buy him a new pair of drawers or two in time for a potential postseason run.

And how ‘bout them Tigers, who not too long ago were looking over their shoulders at the White Sox and Indians but now have a 13.5 game advantage on them.

Much of the credit goes to staff ace and AL Cy Young front-runner Justin Verlander, who now has 23 wins on the year, a 2.36 ERA and a paltry .192 batting average against. If Detroit’s hitters can stay hot — they’re second in the majors with a .316 batting average in September and first in runs scored with 104 — they’ll be a tough out for whichever AL East team they face in the division series.