The U.S. National Junior Team pre-tournament camp begins Sunday at the MSG Training Center in Tarrytown, N.Y., with a 5:30 p.m. practice. Twenty-seven players selected by USA Hockey will compete for 23 spots during the camp which will remain in New York until Dec. 18, before moving to Helsinki, Finland.

It is still uncertain if USA Hockey will make any cuts before heading to Finland, as there are some wide-open battles for roster spots. Due to college finals last week, Sunday was the earliest USA Hockey could hold the camp, so there’s a pretty small window to impress the staff and earn spots.

The only guys who can breathe moderately easy are the goaltenders. With only three in camp and the new IIHF roster rules allowing teams to carry three goalies, John Gibson, Garret Sparks and Jon Gillies are all in.

With 15 forwards vying for 13 spots and nine defensemen getting narrowed down to seven, there’s still plenty to keep an eye on as camp progresses this week. Find out what to watch for after the jump…

It’s always interesting to see what the coaching staff experiments with in camp. They’ll have a pretty good idea of what combos they’d like to see and who might fit with who, but it will all get fleshed out in camp.

Some of the lines that worked so well over the summer may get back together in this camp at least to start to see if the chemistry is still there.

Johnny Gaudreau saw a lot of time with Alex Galchenyuk and a mix of a few different right wingers. It seemed like that line, which struggled to find chemistry much of the summer camp, was most effective when J.T. Miller was on the right wing. It gives the U.S. a potentially formidable top line that can score should those three work well together.

Perhaps the best line was that of Sean Kuraly centering Mario Lucia and Stefan Noesen. As we now know, Noesen’s OHL suspension may keep him out of the WJC if the IIHF honors the league suspension. Noesen is still likely to be in camp just in case, which would be a good reason to give this line another shot in camp. This trio seemed to click fairly instantaneously when Noesen joined Lucia and Kuraly. Should be interesting to watch.

What will be interesting is to see where Riley Barber fits in, particularly if Noesen is unavailable. Barber has been outstanding for Miami and extremely productive. The way he’s played should make him a viable option for any of the first three lines. Since he wasn’t in camp over summer, it’s anyone’s guess as to where they see him as a fit.

The Noesen situation also might dictate what the U.S. does at center. Rocco Grimaldi has been quite effective in games playing on the right wing for North Dakota. The natural center could play either position well at the WJC level, but moving Grimaldi to the wing could free him up for more focus on offense. Could be interesting to see where he fits best for Team USA. Should Grimaldi move to the wing permanently, Team USA could go with Galchenyuk, Vince Trocheck, Sean Kuraly and Cole Bardreau and have a really good mix of skill and grit. Very intrigued to see how this plays out.

The left wing battles are quite tough to project. Gaudreau appears the clear No. 1 guy to play an important scoring role. Mario Lucia and Jimmy Vesey are fairly comparable players on the left side, though Lucia has a little more to offer offensively, while Vesey has better defensive capabilities. Stafan Matteau and Blake Pietila each have the grit and could fill lower-line roles with their strength and physicality, while providing a little bit of offensive pop. With 13 forwards, there’s a chance all five of these guys can make the final roster, but whichever player can provide the most versatility in that 13th F role will earn the spot, more than likely.

On defense, the competition appears to be on among the three offensive-minded guys coming into camp with Shayne Gostisbehere, Mike Reilly and Matt Grzelcyk all providing very similar skill sets. It’s hard to imagine a scenario in which all three are brought to Ufa, but it’s not out of the realm of possibility. All have high-end puck-moving capabilities and skating. All are left shots. Reilly has the best size of the three at 6-1. Grzelcyk has the most international experience and Gostisbehere might be the best defensively. What Team USA plans to do about these three might be the most intriguing decision of them all.

With only three right shots in camp, it is likely Team USA is set on the right side with Seth Jones, Jacob Trouba and Connor Murphy. All three looked good to make the team all year and each makes a lot of sense for Ufa for a variety of reasons.

Where it gets a bit tougher to figure out is with Patrick Sieloff, Jake McCabe and Brady Skjei. Each are vastly different from the other and each brings something different than the rest of the invitees.

Sieloff has the grit and stout defensive play with some moderate offensive ability. McCabe has turned himself into a true two-way defender who is very strong in both zones, perhaps a little more in the D zone. Meanwhile, Skjei is a very strong defense-first kind of defenseman with elite speed and skating to help him contribute offensively on occasion. There are likely spots for two of these three guys to help round out Team USA’s defense and give it more versatility.

The camp should make for some very interesting competition as players have that aforementioned small window to make it happen. Of course a player’s full body of work will be taken into account when going through the final decisions. For some of the perceived locks, it would take a monumental failure in camp to shake their candidacy. It’s obviously an important couple of days for the bubble players to try and establish themselves and earn one of those final open spots.

While the camp is important for the bubble guys in terms of making the team, it also serves another purpose for all players. The biggest thing the camp provides and a big reason USA Hockey has kept this format going every year since 2010 is that pre-tournament tension and competition.

Providing the competitive environment for these players before they even get to Ufa is a good way to get those juices flowing for the demands of the tournament. The brevity of the World Junior Championship means a team has to come together quickly and play a very competitive brand of hockey to have success.

Intangibles might not be as important as physical tools when projecting prospects for future NHL careers, but they’re vastly important in the mentally and physically grinding WJC. The teams that have won have had that perfect mix of high-end skill, speed and that high level of competiveness and/or battle. Some of that can be fostered through the pre-tournament camp, helping make the transition to live games seamless.

It’s not an easy tournament to win, but Team USA’s foundation will begin to take shape starting Sunday.

Follow along on United States of Hockey throughout the camp and World Junior Championship for more Team USA news, notes and analysis. You can follow me on Twitter as well for frequent updates and don’t forget to like the USofH Facebook page.

As a personal side note, today marks the second anniversary of the United States of Hockey’s inaugural post. I am so thrilled to have been able to maintain the blog and watch as it grows by the month. More than anything, I am thankful for all of you who come by and read this blog. Even if you’ve only been here a few times, I appreciate you reading and hope you like what you’ve seen so far. Thanks again, everyone. It’s been a blast so far.