Forsbacka Karlsson had firsthand knowledge of McAvoy's makeup the past two seasons before each signed a three-year, entry-level contract with the Bruins in April. Grzelcyk, a defenseman, was captain as a senior during McAvoy's freshman season in 2015-16. He signed a two-year, entry-level contract April 1, 2016.
Forsbacka Karlsson and Grzelcyk were aware of McAvoy's tendency to play a lot of minutes, strong positional play, and intimidating presence along the blue line long before he averaged 26:12 and worked the point on the Bruins' top power play in the playoffs.
Each has shown plenty of his own strong qualities at the Prospects Challenge.
"[Forsbacka Karlsson] is a smart player, but I still believe he needs to shoot the puck more because good things happen," said Providence coach Jay Leach, who is coaching Boston here. "Clearly he's an intellectual player, he makes nice reads, and supports the puck well on breakdowns. He has proven to be responsible defensively and that's good."
McAvoy said Grzelcyk has the experience to be in the mix for a roster spot this season.
"He's a very dynamic defenseman," McAvoy said. "He can skate effortlessly, has great skills with the puck, is a great passer, and [has the] offensive ability to run a power play. His defensive strengths are very strong and he always finds a way to get his stick on the puck. For a guy his size, he can still play a strong game."
Leach said it's a matter of time before Grzelcyk (5-foot-9, 174 pounds) gets his chance.
"He's poised with the puck; a smaller guy but not afraid to defend," Leach said. "As a coach you try not to fall in love with guys, but [he] is different because he's a good person and he's someone I really root for. I hope he gives himself the best chance in training camp."
Grzelcyk said, "For me, it starts with moving the puck up and being that guy who is reliable on the breakout. Someone who doesn't have to spend too much time in his own zone but is willing to play defense as well, and when I get a shot on the power play, take advantage of it."