Sundqvist, 25, appeared in 75 regular-season games with the Blues in 2018-19, scoring 14 goals with 17 assists and logging 22 penalty minutes. The forward had four goals and five assists in 25 playoff games, helping the Blues capture the 2019 Stanley Cup.
The Blues withstood the suspension of Sundqvist for Game 3 of the Stanley Cup finals for delivering an elbow to the head of Bruins defenseman Matt Grzelcyk. St. Louis went on to claim the Cup in seven games.
Drafted 81st overall by the Pittsburgh Penguins in 2012, Sundqvist was acquired by the Blues in a trade with Pittsburgh in June 2017.