CHANDLER, Ariz. – New England's goofiest guy off the field will be Seattle's most serious matchup problem on the field when all the talking finally hushes long enough for Sunday's playing of Super Bowl XLIX.

In fact, it's not too much of a stretch to argue that Sunday's game hinges on who wins the battle between Patriots tight end Rob Gronkowski and Seattle's "Legion of Boom" defense, which surrendered 11 of its 17 regular-season passing touchdowns to tight ends.

From an outsider's perspective, it would seem borderline frightening to think that "Gronk" holds the key to anything valuable during a week with this many after-hour temptations. But Patriots insiders who swear by Gronkowski's professionalism while on the job might argue that quarterback Tom Brady would be going for a record fifth Super Bowl victory this week had Gronkowski not been so limited because of an ankle injury when the Patriots lost to the Giants 21-17 in their last Super Bowl three years ago.

"When you talk about his demeanor in the meeting room, he's like Tom Brady," offensive coordinator Josh McDaniels said at the Patriots team hotel. "When you talk about the way he prepares and practices, same thing."

Gronk?

The same guy who has been talking about the "Gronk Party Bus?" The bus that people say used to belong to a church in New York and is now dubbed "The Sinners' Bus" and possesses its own Twitter account: @GronkowskiPartyBus?

Apparently so. Otherwise, you know no-nonsense coach Bill Belichick wouldn't stand for any overlap between the larger-than-life Gronk persona outside of football and the necessary conformation and seriousness required to be part of the "Patriot Way."

"Rob always has great energy and enthusiasm for the game," Belichick said. "He's always ready to go, loves to practice, loves to work, works hard in the weight room and competes well all the time.

''You never have to get on Rob and go, 'You know, that wasn't your best,' or that kind of thing. He's always out there working hard.

"I have tremendous respect for Rob and the way he goes about his job."

All over the map

Johnny Manziel should hire Gronk as his tutor. Then again, perhaps Johnny Football would only slow Gronk down when it comes to having a good time off the field.

He comes from a family that's, well, let's just call them fun-loving. Gordie, the father, is "Papa Gronk." Gordie Jr., Dan, Chris, Glenn and Rob are the brothers who have a reputation for "Gronking" their share of beer cans.

Dan played three years at tight end for the Lions. Chris is a fullback in Denver. Glenn, a fullback at Kansas State, might be the next one to join the NFL.

Can any of them top Rob in terms of goofy marketability? Doubtful.

Let's just say Gronk has spent the week talking about a wide spectrum of topics, many having nothing to do with football.

There was the magazine photo shoot where he apparently was naked except for some well-positioned kittens.

"Who doesn't love kittens?" Gronk says. "Kittens are cool."

Numbers and injuries

There was the time during Super Bowl Media Day when he was asked to read an excerpt from the erotic book titled "A Gronking to Remember."

"You can laugh about it and everything," Gronkowski said. "It's cool. But at the same time, you can't really get caught up in all of it because you're here for a job. And that job is to win a football game."

From an on-field matchup standpoint, one can argue that the Patriots lack an outside receiver. Then again, that's an argument that doesn't recognize Gronkowski as an evolutionary tight end. One capable of morphing into several roles, including that of a 6-6, 265-pound outside receiver.

As a second-round draft pick in 2010, Gronkowski caught 10 touchdown passes, the most by a rookie tight end since 1970. In 2011, his 17 receiving touchdowns (he also had one rushing TD) set the record for a tight end.

In 2014, the unanimous Associated Press All-Pro first-team selection caught 82 passes for 1,124 yards (13.7) and 12 touchdowns while returning from knee, back and multiple forearm surgeries that had caused him to miss 14 games the previous two seasons. Then, in two postseason games, he caught 10 balls for 136 yards and two touchdowns.

Matchup issues

"Gronk is a phenomenal athlete," Brady said. "He's got great presence, a great understanding of the game and how to get open on different types of cover guys, whether they're big or small."

The Seahawks will look to match up big and talented safety Kam Chancellor on Gronkowski. The Patriots will move Gronkowski around, searching for favorable matchups that could include putting him in the slot against nickelback Jeremy Lane, considered the LOB's weakest link.

Although Seattle surrendered a league-high 65 percent of its touchdown passes to tight ends, the figure is a bit deceiving heading into the Super Bowl. That's because seven of those touchdowns came in the first six games. Since then, tight ends have caught only 52 balls for 538 yards (10.3) and four touchdown passes, none of them in the postseason.

Then again, there might be only one Gronk, on the field as well as off.

"I don't know if we have many guys that work harder or care more about doing their job exactly right than he does," McDaniels said. "At the same time, we love his demeanor, the fact that he can have a lot of fun doing this."

Mark Craig • mcraig@startribune.com