The forward was a restricted free agent. He received a qualifying offer July 26.
"With Alex's pedigree and being only 23-years-old, we feel as if there is still plenty of room for growth in his game," Blackhawks general manager Stan Bowman said. "He is just scratching the surface of the type of player we feel he is capable of becoming. This will be an important season for him to perform consistently and contribute offensively. His size and skill are a unique combination that make him an intriguing option for our coaching staff to utilize anywhere in the lineup."
Nylander did not play last season after having Dec. 21 surgery for a torn meniscus in his left knee sustained during the 2020 Western Conference First Round. The Blackhawks lost the best-of-7 series in five games to the Vegas Golden Knights.
Nylander scored an NHL career-high 26 points (10 goals, 16 assists) in 65 games for Chicago in 2019-20. He did not have a point in eight Stanley Cup Playoff games.
Selected by the Buffalo Sabres with the No. 8 pick in the 2016 NHL Draft, Nylander has scored 32 points (13 goals, 19 assists) in 84 games.
