Superstitions are sometimes easy to hide. Michael Jordan wore North Carolina shorts under his Bulls shorts. Wade Boggs ate chicken before every game. Patrick Roy conversed with his posts.

In the 21st century, one particular superstition is blatant: the playoff beard. In the postseason, especially in baseball and hockey, the art of not shaving is part of the modern culture. A lack of facial hair is a playoff surprise.

Luckily, the modern era also provides specialists to help analyze such men. Dr. Allan Peterkin is pognologist (beard scholar), who has written three best-selling books on facial hair. He has been published in the New York Times, The New Yorker, Sports Illustrated, The Wall Street Journal, Men's Halth, GQ and Esquire.

"Men bond around facial hair," Peterkin says. "It's one of the few things guys can do that women can't."

Some credit the New York Islanders dynasty of the 1980s as being pioneers of the playoff beard. Peterkin says there is good reason why this macho superstition has spread.

"The idea of a playoff beard, which has extended beyond hockey to other sports, is that you're in this together," Peterkin says. "You're manifesting your loyalty to your team. It's a real kind of bonding team experience. It's very masculine."

In 2013, the Boston Red Sox provided notable images with beards that drooped a few inches under chins. Mike Napoli, Jonny Gomes, David Ross and Jared Saltalamacchia took the playoff beard to the next level. Of course, Fenway Park bullpen police officer Steve Horgan had his facial hair eternalized with a bobblehead.

The Kansas City Royals and San Francisco Giants are not doing too shabby themselves this fall. The Giants had practice two years ago, and for some players, two years before that (There is no Brian Wilson in San Francisco anymore, but Sergio Romo, the closer in the 2012 World Series as well, has done well as a beard replacement).

In the Bronx, the New York Yankees have a history, spearheaded by the late George Steinbrenner, of disallowing players to grow facial hair. Peterkin notes the Yankees are the final remains of a previous error in sports that held athletes to different appearance standards.

"You had to sport an All-American look of healthy rosy red cheeks and stuff like that," Peterkin says. "Facial hair was thought of as kind of dark. Now, it's opened up. The athletes say they're not corporate slaves. They're free to express themselves."

Hypothetically speaking, when ThePostGame asked Peterkin if he would grow hair as a member of the Yankees, he chuckled and considered such a situation.

"I like the freedom," he says. "I think most guys like the freedom to go back and forth and do what they want. I guess it would depend on what the salary was."

Outside of sports, Peterkin, a spokesman for Dove Men+Care Face Range, is currently advocating five notable forms of fall facial hairstyle. The "Stubble" is the trendy, youthful look. The "Mustache" shows a loyalty to facial hair history. The "Full Groomed Beard" shows facial hair confidence. The "Wild and Untamed," displays a lack of care and can be considered the "playing hard to get" of beards. Meanwhile, clean-shaven is not a poor choice of facial hair. It is clean and Peterkin says, "you don't have to break rules to make your point."

Peterkin was a judge at the 2012 National Beard and Mustache Championships in Las Vegas. He resides in Toronto, where he is an associate professor of psychiatry and family medicine at University of Toronto.

Related Story: Is Time Running Out To 'Fear The Beard?'

-- Follow Jeffrey Eisenband on Twitter @JeffEisenband.

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