Joe Flacco's got one going now, a scruffy, brown growth that either makes him look tough and swashbuckling or like one of those Amish guys in the ads for electric heaters, depending on your point of view.
As you may know, the Ravens' quarterback broke it out right before his team's final regular-season game against the Cincinnati Bengals.
"Really, I usually get it to a week's length and then I cut it off for the game," he said that week. "But a couple (teammates) said I should probably try to keep it, and I said 'All right, why not?'"
Sure enough, the beard became an immediate hit with a certain segment of Ravens fans. Some even grew their own beards in his honor, splashing the news all over their Facebook pages.
And now the Flacco beard will get even more scrutiny after his terrific performance (25-of-34 passing for 265 yards and two touchdowns) in the Ravens dominating 30-7 playoff win over the Kansas City Chiefs Sunday.
The TV announcers at Arrowhead Stadium said Flacco "looks like Grizzly Adams with that beard."
But that's become a cliche, and it's far too facile a cliche to use with Flacco, who's not exactly known for bringing attention to himself.
Plus he's probably too young to know that Grizzly Adams was a legendary mountaineer and grizzly bear tamer in the Old West in the late 1800's, forever immortalized in a corny TV show in the mid-70's starring Dan Haggerty.
The last time a beard in professional sports got this much attention was during the baseball playoffs last fall, when San Francisco closer Brian Wilson took the mound with a luxurious beard that he dyed jet black.
The beard made Wilson look like a cross between a young Fidel Castro and Joaquin Phoenix the night he gave that bizarre interview to David Letterman.
But Wilson is a nut, an out-sized flamboyant personality who needs attention the way the rest of us need oxygen.
How else to explain all his histrionics whenever he closed a game, the crazy, samurai-like crossing of his arms that he said was an homage to the MMA fight game, his Christian faith and the memory of his father?
Whew. Flacco's personality is about as different from Wilson's as it gets. Flacco didn't grow a beard for attention. He grew it because he was too lazy to shave and his teammates liked the look.
And now he's stuck with it. Because how can you shave off a playoff beard when it's brought you so much good luck?
Answer: you can't.
If the Ravens so much as see Flacco reaching for a razor now, they'll kill him.
But let us know what you think.
That sound you heard was probably Grizzly Adams rolling over in his grave.