One of the Flyers biggest improvements from the 2018-19 season to the 2019-20 season was adding veteran defensemen that aided the penalty kill and fortified defensive play at five-on-five.

One of those additions is currently a pending free agent, Justin Braun. The other, Matt Niskanen, still has one year remaining on his contract.

In a surprising decision, Matt Niskanen will announce his retirement, according to multiple reports. He has reportedly also informed both the Flyers and his teammates of this decision.

Niskanen, 33, scored eight goals and had 33 points in 68 games with the Flyers this season, his first with the organization. Niskanen chooses to retire after 13 seasons in the NHL, spending time in Dallas, Pittsburgh and Washington before being traded to Philadelphia. He was a member of the 2018 Stanley Cup champion Capitals.

In his career, Niskanen scored 72 goals and had 356 points in 949 regular-season games.

For Niskanen, this isn’t necessarily a completely surprising move. He was one of the veterans on this team and seemed to be experiencing the stresses of being away from family during the NHL return in the Toronto bubble.

For the Flyers, this completely changes their offseason. If Niskanen retires, his $5.75 million cap hit will be freed up, allowing the Flyers more flexibility when free agency begins later this week. The Flyers have intentions to re-sign defenseman Braun to keep a veteran presence on the blue line. They also still need to give contracts to Phil Myers and Nolan Patrick, and could explore the trade and free agent market at other positions with the added cap space.

Kevin Durso is Flyers insider for 97.3 ESPN and Flyers editor for SportsTalkPhilly.com. Follow him on Twitter @Kevin_Durso.