Moulson played a key role in the on-ice development of Tavares, who was chosen No. 1 by the Islanders in the 2009 draft. They also were close friends off the ice.
"He's been there for all the success I've had," the 23-year-old Tavares said. "The little things he does that have helped my game, we were door-to-door neighbors my second year. How long we've known each other. The impact that he made, he and his family, how much they helped me off the ice. Words can't really describe how much he was there for me.
"It's part of the game, part of the business, you understand that. I'm sad to see him go, but it's what the team thought was best. We have to go forward now, starting tomorrow."
The Islanders will welcome the New York Rangers on Tuesday night, which will mark Vanek's debut with the team.
Islanders coach Jack Capuano didn't have much advance notice of the deal, but once it was made he quickly decided that Vanek would join the top line.
"Anytime you trade a top player for a top player, that's where he's got to go," Capuano said. "He's very skilled, and he's good with the puck. He shoots the puck really well. He's got good size so, he'll start with Johnny and Kyle and we'll see where that plays out."
If it works well, the Islanders hope that comfort zone and a familiarity with New York forward Michael Grabner — a fellow Austrian — will make the difference once contract talks begin in earnest.
"We haven't even had those conversations," Snow said. "Our focus has been to acquire Thomas and get him on a flight here, and get him situated and comfortable and get him ready for today's practice and tomorrow's game.
"He's a high-end talent. An All-Star caliber player, big body. He can skate and obviously score goals at an elite level, he's a high-caliber person off the ice, so for us, we're getting a great addition to our team."