"My mother was born there," said Thornton before leaving on Wednesday. "I have aunts, uncles, second cousins, all kinds of family over there. It will be good to see them."
The Bruins flew to Belfast after Wednesday night's game with the Capitals, and they'll continue their preseason preparations in Northern Ireland through the weekend before moving on to Prague.
Thornton was born and raised in Oshawa, Ontario and has never been to Northern Ireland before, but he's always felt a pull toward the old country and taken pride in his Irish heritage. His mother, Catherine, even named him after the John Wayne character in the classic film, The Quiet Man, about an American boxer who retires to Ireland and finds love there.
With 496 penalty minutes in 290 career NHL games, plus another 2,468 PIMs in 605 AHL contests, maybe mom knew something about her son's future role as an enforcer when she decided on the name.
This week, Catherine Thornton might just get to see her son ply his trade in her native land for the first time, as the Bruins' tough guy has turned this exhibition game into a chance for a long-awaited family reunion.
"I'm flying my mom over, and her family's already over there," said Shawn Thornton. "She's staying at her cousin's house. She's really excited. She hasn't been back since she left 47 years ago."
Thornton is pretty excited himself, though he knows he won't have too much free time to explore the city of his forebears.
"We're so busy over there, but I'm going to try to sneak away from the guys for a few hours to see my family, maybe get them to take me around town and show me a few things," said Thornton. "I've got a lot of people I've got to squeeze into the couple of hours I have on Friday afternoon."
After Friday, the Bruins take on the Belfast Giants, buoyed by some of the other top players in the British Elite Ice Hockey League, on Saturday, then move on to Prague on Sunday. Even though the Bruins will be the road team against Belfast, they'll have a healthy rooting section on hand thanks to the Thornton clan.
"They'll all come to the game," said Thornton. "I've got about 20 tickets. The guys were good enough to give me theirs that they weren't using, so it will be fun."
It will be fun for Thornton as well, who never imagined he'd get a chance to play in Belfast, at least not in a Bruins uniform.
"Not an NHL game no. I figured maybe a British, whatever, Premier League at some point in my career," said Thornton. "But it's pretty cool. I've been pretty lucky in my four years here. My first year we had an exhibition game in Newfoundland after I had played there for four years [with St. John's in the AHL] and hadn't been back. Now we're going to Belfast where my mom's family still lives, so it's going to be good."
The only question left is whether Thornton will meet more Irish people on this trip than he usually encounters walking around his adopted neighborhood of Charlestown.
"I don't know, it's probably 50-50," said Thornton. "I guess I'll find out. I'll see how many scally caps I can count over there."
