INDIANAPOLIS - It's as prominent a facial feature as Joe Paterno's nose.
The players closest to Bill O'Brien often tease him about it.
They even have a nickname for his cleft chin.
"Butt chin," Patriots quarterback Brian Hoyer said.
Tom Brady also likes to pick on O'Brien's receding hairline, according to Hoyer - not that the Patriots' offensive coordinator is the butt of every joke. He likes to give as much as he takes.
It's the kind of atmosphere O'Brien has fostered with his quarterbacks, and one that stands in contrast to his public persona as a fiery, intense competitor.
"He's that Boston guy. He grew up in Andover [Mass.]," Hoyer said Thursday. "He's just tough and a hard worker, very passionate about what he does. But also there's a great humorous side to him. When you're meeting 10 hours a day, you got to lighten the mood. That's one of the things I'll miss about him most."
O'Brien, of course, is five days from taking on the gargantuan task of replacing Paterno as Penn State's next head coach. But first there is a football game - something called Super Bowl XLVI - that has the 42-year-old preoccupied.
Since being named Paterno's successor last month, O'Brien has had to juggle both jobs. This week, he has dealt with preparation for Sunday's game, a diluted recruiting class, and unending questions about his overall predicament. But he handled the barrage with poise and the occasional joke.
O'Brien said he gets his Irish temper from his mother, but his sense of humor from growing up in the Boston area and from his two older brothers.
"They have great senses of humor," O'Brien said. "It's like that New England sense of humor - a little bit of a wise guy. Hopefully, people take it the right way."
O'Brien isn't likely to show this side as much with the Nittany Lions. At the NFL level, coaches and players are sometimes more like peers.
"It's like brothers teasing each other," said Hoyer, Brady's backup. "Obviously, the relationship is a little bit different when you go to college."
O'Brien coached at the collegiate level for 14 seasons, the last time at Duke in 2005-06. So he has experience with coaching teenagers. But he has never been a head coach at that level. He and others say he will have no problems being a disciplinarian.
