The joke making the rounds in the wake of another Michigan loss to a rival: Jim Harbaugh already is wearing his Halloween costume. He’s dressed as a football coach.

This is what happens when you put yourself out there — and no one puts himself out there quite like Harbaugh — and fail to deliver. You get labeled an impersonator.

Michigan has been here before. Former UM coach Brady Hoke was harangued by his own fans as something of a fraud. Nice guy. Good recruiter. Awful game coach. In over his head. Yet over his first 31 games at Michigan, Hoke went 24-7, including 1-1 in bowl games and 2-2 against rivals Ohio State and Michigan State.

Harbaugh just completed his 31st game. His record? 24-7 overall, 1-1 in bowls and 1-4 against OSU and MSU, to whom the Wolverines lost on Saturday in rainy Ann Arbor. And you thought Hoke was a fooler? Harbaugh’s results, especially in the biggest games, smacks of more trick than treat.

I remain convinced Harbaugh is good for college football. He diverts attention from the NFL, which pleases the NCAA, he tweaks the NCAA whenever possible, which pleases critics of the NCAA, and he provides goofy amusement in a business that takes itself too seriously. A bubble-gum chewing and barefoot Harbaugh recently attempted a jackknife dive off a 5-meter platform at UM while wearing khakis and his “M” hat. The stunt raised my suspicions, but even staged spontaneity can be worth watching.

But is Captain Khaki good for Michigan? I still think so, largely because I don’t see the Wolverines backtracking the way they did under Hoke, who after going 24-7 went 7-9 before he was fired.

But the sands are shifting. Harbaugh no longer is a sure thing. It would help if he had a sure-thing quarterback. Wilton Speight was just ordinary before cracking three vertebrae against Purdue on Sept. 23, an injury that could keep him out for the rest of the season. His replacement, John O’Korn, has been shaky, including throwing three interceptions in Saturday’s 14-10 loss to Michigan State.

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On the other hand, Harbaugh was supposed to be the quarterback whisperer, but so far he mostly just blows hot air at officials. But then there is a lot of what-you-see-is-not-what-you-get going on in the Big Ten at the moment. Harbaugh isn’t the only pretender. Look at his team, and a few others.

Michigan. It’s the quarterback, stupid. If you don’t have one it catches up with you. The Wolverines could lose four more games. They still must play at Indiana, at Penn State, at Wisconsin and home against Ohio State.

Ohio State. Imposter is too strong a description, but it will take more than blowouts against Rutgers, Maryland and probably Nebraska on Saturday to convince me OSU can challenge Alabama and Clemson. Just making the playoffs proves little if you can’t compete once there. That 31-0 Fiesta Bowl loss to Clemson had many crying “overrated.”

Penn State. I waver on whether the Nittany Lions and coach James Franklin are for real. Currently, I’m in the camp that thinks PSU is getting more love than it deserves. The offensive line remains suspect, which explains why Heisman candidate Saquon Barkley rushed for only 75 yards against Northwestern one week after rushing for 56 against Indiana.

Wisconsin. The Badgers have played whom? That’s right. No one. Let’s see what happens when they welcome surprising Purdue — the Boilermakers actually are being undersold at the moment — into Camp Randall Stadium on Saturday.

Until then, keep your eye on Harbaugh, which is just how he likes it.