The four participating schools in the 2015 Frozen Four don't all have the same degree of offensive fire power, tradition or experience in college hockey's pinnacle event. However, one thing the four schools have in common is a goaltender that ranks in the top 15 nationally in save percentage.

There is also no shortage of experience between the four starting goaltenders in the Frozen Four. Nebraska-Omaha's Ryan Massa is a senior while Providence's Jon Gillies, Boston University's Matt O'Connor and North Dakota's Zane McIntyre are all juniors.

The three juniors have been the undisputed man between the pipes for their respective teams this season and Massa has carried the bulk of the load for UNO. Two of the goalies, McIntyre and Gillies, have been drafted by an NHL team while O'Connor and Massa are NHL free agents.

It is possible, if not likely, that all four will be playing professional hockey come next fall. Gillies and McIntyre are hot commodities that their respective NHL organizations would like to sign after this weekend. O'Connor, despite some of his deficiencies, is the most coveted NCAA free agent prospect at the position. Massa will graduate in May.

Player Bio: Jon Gillies

When Jon Gillies is on, there is really no better goaltender in the country. He's big, he's athletic and he's technically sound. The Calgary Flames prospect has had a few off games, but if you're a coach looking to win one game, Gillies is your guy.

The starting goaltender for the U.S. team at the 2014 World Junior Championship, Gillies has international experience. When Gillies is playing his best, he's eating all shots or pushing potential rebounds right into the corners. Usually, it's easy to see if Gillies is on top of his game early in the first period. He seems to thrive when getting rubber and when he's able to get right into intense action.

As Leaman said after the regional final against Denver, Gillies was his team's best player. He will need to be again this weekend in Boston if Providence is to win its first NCAA championship in school history.

(Photo Credit: Matt Dewkett)

Player Bio: Ryan Massa

The senior from Littleton, Colo. has played the least minutes of any of the four projected starters for Thursday's Frozen Four semifinals. Massa was pulled from his the first game of the NCHC Quarterfinals against St. Cloud and didn't play the next night. He also didn't play on senior night a week earlier.

He's put up terrific numbers, but missed four games at the start of the second semester in which he did not even dress. He was out due to injury, but he's been at the mercy of head coach Dean Blais who is notorious for having a fickle hand with goaltenders.

An NCHC Second Team All-Star, Massa's numbers jumped exponentially from his junior to senior year. After playing 21 games as a freshman, the Fargo Force (USHL) product played just three games as a sophomore. It could be said his career at UNO has come full circle.

(Photo Credit: Matt Christians)

Player Bio: Zane McIntyre

The Boston Bruins prospect is a Hobey Baker Award Hat Trick Finalist along with Jack Eichel and Jimmy Vesey. He will likely win the Mike Richter Award, given annually to the best goaltender in college hockey. The Grand Forks, ND native has lived his childhood dream of playing college hockey for UND.

McIntyre and UND were painfully eliminated from last year's Frozen Four when a Minnesota shot in transition beat him with 0.6 seconds left on the clock.

A sixth round selection in the 2010 NHL Draft, he will almost assuredly sign with the Bruins as soon as the season is over. McIntyre has played all but 55 minutes between the crease this year. Playing in back of a stout defense and overall team with good puck possession numbers, McIntyre hasn't been tested that often, but he's been extremely solid. He has exceptional focus, rarely giving up a soft goal. He has proven the ability to steal games when necessary.

(Photo Credit: Matt Christians)

Player Bio: Matt O'Connor

The Toronto, Ontario native has taken over as the full-time starting goaltender in his junior season on Commonwealth Ave. due to Sean Maguire's medical leave from the program for the entire year. The tallest of the four goaltenders in the 2015 Frozen Four, O'Connor takes up a lot of net coverage.

NHL scouts love his size and he's certainly taken advantage of added exposure this season to gain serious NHL looks. O'Connor is close to graduating in three years and will sign with an NHL organization after the season as an undrafted free agent.

He's put up terrific numbers, but he has benefited from playing in front of a talented team that has controlled puck possession and done a nice job limiting shots and keeping opposing teams to the perimeter for the most part. He's made some highlight reel saves including a glove save on UMass Lowell's Zack Kamrass in the Hockey East championship game.

O'Connor does have a tendency to give up the occasional soft goal or allow rebounds. He admitted last season his need to improve his rebound control and he has. He's certainly developed nicely at BU and will parlay that into a nice NHL contract, but the question remains, is his size and inflated numbers playing a role in that?

Evolution of the position

It's no secret how much the position has evolved over the past couple decades. Sure, there are reasons besides goaltending for why Boston University, North Dakota, Omaha and Providence have advanced to the TD Garden.

But, taking a simple statistical look at save percentages, it's not hard to figure out how the goaltending position has gotten better over just the past decade. Better equipment and better coaching certainly play a role in that.

The 2005 Frozen Four, in Columbus, Ohio, featured four WCHA teams. Colorado College had the best team save percentage (.919) while North Dakota (.912), Minnesota (.910) and that year's national champion Denver (.909) were bunched closely together.

This year's Frozen Four participants have team save percentages of .928 (Providence), .927 (Omaha) and .925 (Boston University and North Dakota).

Another change in the position over the past few decades has been the added size of goaltenders. Massa, at six-feet, is the smallest goaltender in the Frozen Four. McIntyre (6-2), Gillies (6-5) and O'Connor (6-6) stand tall in the crease.

Frozen Four Save Percentages (2005-2015)

Year NCAA Champ Runner-up Semifinalist Semifinalist 2005 Denver (.909) North Dakota (.912) Colorado College (.919) Minnesota (.910) 2006 Wisconsin (.928) Boston College (.924) North Dakota (.922) Maine (.910) 2007 Michigan State (.914) Boston College (.922) Maine (.913) North Dakota (.905) 2008 Boston College (.921) Notre Dame (.910) North Dakota (.927) Michigan (.922) 2009 Boston University (.915) Miami (.907) Bemidji State (.908) Vermont (.904) 2010 Boston College (.916) Wisconsin (.902) Miami (.921) RIT (.918) 2011 Minnesota-Duluth (.907) Michigan (.924) North Dakota (.910) Notre Dame (.896) 2012 Boston College (.925) Ferris State (.921) Union (.930) Minnesota (.907) 2013 Yale (.910) Quinnipiac (.930) UMass Lowell (.928) St. Cloud (.905) 2014 Union (.924) Minnesota (.929) Boston College (.919) North Dakota (.916)

West Region Champ Northeast Region Champ Midwest Region Champ East Region Champ 2015 North Dakota (.925) Boston University (.925) Omaha (.927) Providence (.928)

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Jeff Cox covers college, junior, high school and prep hockey, NCAA recruiting and NHL Draft prospects. Follow him on Twitter @JeffCoxSports.