The tournament could also include Sabres prospects Josh Bloom (third round, 2021) and Olivier Nadeau (fourth round, 2021), both of whom have been invited to Canada's National Junior Team summer development camp in July.
Rosen, 19, spent the majority of this past season playing in a limited role for Leksands IF of the SHL, Sweden's top professional league. The forward signed his entry-level deal with the Sabres on May 31.
Rosen previously represented Sweden at the U-18 World Championship in 2021, where he tallied seven goals and nine points in seven games and was selected as a top-three player on his team.
"He can really shoot the puck," Sabres director of player development Adam Mair said. "He can skate, and he's got offensive abilities. So, when I think about how he can impact games, he can do that with his shot and with his offensive skills. That's the kind of player he is.
"He's effective off the rush, he's dangerous off the rush, he can score from distance. And that's something that's really hard to teach. So, we're excited about him long-term."
Read more about Rosen and the rest of the Class of 2021 here.