Mathew Barzal of the New York Islanders celebrates his goal...

Mathew Barzal of the New York Islanders celebrates his goal at 9:32 of the second period against the New Jersey Devils at the Prudential Center on Sept. 25, 2015 in Newark. Credit: Getty Images / Bruce Bennett

WASHINGTON -- Some thoughts after Sunday's final preseason game and evening roster moves:

Mathew Barzal was always going back to Seattle of the WHL, whether it was at the end of camp (which is what happened), after the first weekend of the regular season (my thought) or after nine NHL games. The 18-year-old has shown ample reason this camp why now-retired director of scouting Trent Klatt nearly jumped out of his seat at the Isles' draft table when the Bruins passed on Barzal with picks 13 through 15. The kid is legit and he knows it -- cocky in a good way, which is how someone in the Isles brain trust described an 18-year-old Ryan Strome after his first camp.

But if you believe the Islanders are built to win now, then they can't afford to help an 18-year-old through the ups and downs of learning the NHL game. Barzal played Sunday night in John Tavares' spot between Anders Lee and Strome, and T.J. Oshie barreled right past Barzal for an easy tap-in goal to open the scoring.

You can live with that if your team is in the midst of a rebuild or the 18-year-old fills a need. Barzal will pile up points in the WHL this season, probably play at the World Junior tournament and be ready to challenge for a center spot as a 19-year-old.

Kirill Petrov is a different matter and it's a situation that bears watching. He's 25, has been a pro making serious (tax-free) dough in his hometown of Kazan in Russia for years and his hope in finally coming to North America was to play in the NHL. That may still happen in very short order, of course, but not yet. How long he's willing to ride buses in the AHL, with no language support for a guy who speaks very little English, is unknown. My feeling is if he's there longer than a month, he might not stick around.

Eric Boulton's situation will be resolved by Tuesday as rosters need to be finalized by 5 p.m. This is one of those situations where the majority of the fans feel a certain way and everyone around the team feels the opposite. For his limits on the ice as a 39-year-old one-time enforcer, Boulton is an important person with his teammates. John Tavares, in particular, leans on Boulton to help take the temperature of the room. That's stuff that no one sees but makes a difference in a roomful of, you know, human beings who like and respect one another.

That may not change many minds among the fans who don't get to be around the players. But it's the reason why Boulton is still here and there's a tough decision to be made on him.

The likely reason for the Barzal and Petrov moves so quickly after the game was for Garth Snow and his staff to see who's out there on waivers Monday, and there will be a lot of decent players on waivers. The Isles have 13 forwards locked in, plus seven defensemen (plus Thomas Hickey, on IR for the next couple weeks). Goaltending is where things get interesting.

Jaro Halak is supposed to resume practicing with the team Tuesday, but I'm guessing Monday is an important day to figure out if his nagging upper-body injury is the sort of thing that will last into the season. If it is, the Islanders surely would be looking for an NHL-ready goaltender to team with Thomas Greiss. Stephon Williams has looked good, but I'm not sure he's ready for the possibility of playing NHL games.

Would the Isles gamble on Kings prospect Jean-Francois Berube, who has been an AHL star in a crowded pipeline? Would Snow rather try to swing a trade for one of Calgary's three goaltenders? If there's a move like that coming Monday or Tuesday, you can bet Halak's injury is worse than initially thought.

But if Halak can practice fully this week and be up to speed by next week, then it doesn't appear worth the cost of trying to pick up a goaltender. Not with Williams as Bridgeport's No. 1 and Christopher Gibson in the system now as well.

That second scenario means, of course, that Greiss almost certainly goes back-to-back against the Hawks this weekend. Not ideal to say the least.

The Brian Strait-Marek Zidlicky pairing didn't exactly wow anyone Sunday night, but it was their first game together and they were playing first-pair minutes, not third-pair. Jack Capuano said Zidlicky doesn't skate much in the summer and prefers playing preseason games, so perhaps he's just getting warmed up. But it's been a slow start for the only new addition to the Isles' blue line.

Ryan Pulock hasn't played a shift this preseason on the left side, by the way. So I don't think he'll suddenly jump over there to move Strait out of the opening-night lineup. Adam Pelech had a good camp, but he's a year or two away from challenging for a role.

Pulock had some nerves Sunday night, but I think he'll end up getting some games. Zidlicky isn't going to play all 82 -- neither, frankly, is Travis Hamonic or Johnny Boychuk, based on their injury history -- so all is not lost if Pulock isn't in there Friday or goes down to play some games in Bridgeport.

After a CBA-mandated day off on Monday, the Isles practice at the John McMullen rink on the campus of the Naval Academy on Tuesday and Wednesday. A little getaway with the final squad to bond.