Maatta, 26, tallied 17 points (4-13=17) in 65 games last season with the Blackhawks, while averaging 18:25 time on ice. In nine playoff games, he led the team with a plus-seven rating and paced the defensemen with three goals and six points (3-3=6), while managing 18:17 TOI.
Prior to joining Chicago, Maatta spent six seasons with Pittsburgh from 2013-19 after being selected by the Penguins in the first round, 22nd overall, in the 2012 NHL Draft.
A two-time Stanly cup winner with Pittsburgh in 2016 and 2017, Maatta amassed 124 points (29-95=124), 118 penalty minutes and a plus-61 rating in 427 career games with Pittsburgh and Chicago. In 78 career playoff games, the 6-2, 210-pound blueliner totaled five goals and 22 assists for 27 points.
The native of Jyvaskyla, Finland has represented his country at multiple international events, including a bronze medal win with Team Finland at the 2014 Olympic Winter Games and a fourth-place finish at the 2016 World Cup of Hockey. He also appeared in three IIHF World Junior Championships from 2011-13, and in 2011 was the youngest player to ever represent Finland in that event, while also competing that year at the IIHF Under-18 World Junior Championship.
As part of the London Knights of the Ontario Hockey League, Maatta won back-to-back OHL Championships in 2012 and 2013, highlighted by 37 points (10-12=37) and a plus-21 rating in 40 postseason games. He also collected 13 goals and 57 assists for 70 points in 115 regular season games over that span.
Morrison appeared in 17 games last season with the Fort Wayne Komets (ECHL), tallying six goals and 13 assists for 19 points.