PITTSBURGH -- UMass-Lowell goaltender Connor Hellebuyck is a big — literal — reason why his team is participating in this week’s 2013 Frozen Four in Pittsburgh.

The 6-foot-4, 200-pound freshman is one of three finalists for this year’s Hobey Baker Memorial Award, given annually to college hockey’s top player. He has won 20 of 22 starts, owns the nation’s top goals-against average (1.31) and save percentage (.953), and, there is no arguing his effect.

But Hellebuyck isn’t the sole reason the Northeast Regional champion River Hawks met West Regional champion Yale in Thursday’s first national semifinal game at the Consol Energy Center. Three of UMass-Lowell’s six postseason games have been decided by one goal, which means guys play serious keep-away in front of him.

UML’s Connor Hellebuyckhas won 20 of 22 starts and owns the nation’s top goals-against average (1.31) and save percentage (.953).

“Everybody's pitching in on team defense,” said UMass-Lowell head coach Norm Bazin, who preaches that approach. “And, obviously, you don't go anywhere without a great goalie. All four teams have gotten here because of good goaltending. So it's going to be an exciting weekend.”

East Regional champion Quinnipiac and Midwest Regional champion St. Cloud State were to follow UMass-Lowell and Yale with Thursday’s second national semifinal game, at 8 p.m. ET. Saturday’s national championship game is set for 7 p.m.

Mass-Lowell’s immediate challenge was bottling up Yale’s Bulldogs.

“I feel like one of the underlying themes of our team is team defense and blocking shots,” said UMass-Lowell’s team captain Riley Wetmore, a senior forward  “I feel like a lot of  people don't look at that, but that's why Connor has been doing so well. I feel like it's a team game and he'll tell you that as well.

“His poise back there, you see him, he's kind of boring to watch at times because he's always in the right position and he is such a good goaltender. But when you have a team buying in and everyone blocking shots, it really does help him out.”

And, shot blocking isn’t all; offensive participation is required from Hellebuyck’s defensive-minded mates. UMass-Lowell ranked third in Hockey East Association scoring offense (3.0 goals a game) and tied Providence for second in scoring defense (2.33) this season. The team also yielded a conference-best 2.00 goals per game.

“We've continued with our group defense approach,” said Bazin, who’s in his second season at his alma mater. “It's worked well for us. The guys presently are playing very hard for each other. They're very proud students here at UMass-Lowell. We've got good leadership. Certainly had great goaltending here of late and strong team defense. That's been our formula for our recent success.”

The defensive buy-in is led by Chad Ruhwedel, one of the UMass-Lowell defensemen regularly fronting Hellebuyck. The 5-foot-11, 188-pound junior from San Diego, Calif., logs lion minutes, though not at the rate he did a year ago, and he mixes and matches with mostly blue-line underclassmen.

As the defensive anchor, Ruhwedel -- an assistant captain -- earned first-team Hockey East All-Conference and Northeast Regional All-Tournament Team honors.

“He's been a real presence for us,” Bazin said. “He's one of six defenders that play consistently, and he's added to our special teams. I think he's coming of age, and maturing into a very good defender apart from the offensive contributions that have been obvious since he stepped foot on campus.”

And, Ruhwedel has been able to catch his breath. Buttressed this season by redshirt junior transfer Joe Houk, sophomores Jake Suter and Zach Kamrass, and freshmen Gregory Amlong and Christian Folin, Ruhwedel hasn’t had to play every minute.

“I think one of the highlights of Chad is we've cut his ice time down this year because we've had more support around him and it's been better for Chad,” Bazin said. “I think he's improved because of it. Last year, we were forced to play him a little bit too much at times.”

Indeed, Ruhwedel’s seven goals, 16 assists and 23 points -- through 40 games, to date -- ties him for third among defensemen in the powerful Hockey East.

“That's definitely worked out for us this year,” Ruhwedel said of his 2012-2013 reinforcements. “Buying into the system that coach has integrated has really paid off in the second half. But a lot of our defense comes from our goaltending. When you have good goaltending, the defense is a lot easier for us. So we couldn't be happier for him.

“Another good point is our forwards participate a lot in our D-zone coverage and all that kind of stuff. So definitely a team effort and it seems to be working in the second half.”

The first half wasn’t so hot for the River Hawks, who began the season 2-6-1 before righting themselves. That stretch included two meetings each against the defending national champion, Boston College, and the University of New Hampshire, another Northeast hockey power, plus a road game against Colorado College.

“It gave us a barometer of where we were, and obviously those teams were stronger to start the season than we were,” Bazin said. “And we've since improved.  We've had a good stretch the second half, to point here where we're one of the four participants in the Frozen Four.”