The defenseman will be sidelined three-to-six weeks with the ailment, thereby forcing him to miss several regular-season contests as well as the upcoming All-Star Game, which the Lightning will host on Jan. 28.
Rielly is also sixth in scoring at his position league-wide, and is already only five points off his career high of 36 set two seasons ago.
Superstar center Auston Matthews will also be in attendance, and the addition of Toronto's best defenseman would certainly garner further interest in the event from one of hockey's largest fan bases.
The Boston Bruins will already be represented by Brad Marchand, and while the young Charlie McAvoy would be an exciting replacement - and make no mistake, his time will come - it's Torey Krug who could add more black and gold to this year's All-Star festivities.
Krug is coming off a breakout 51-point campaign in 2016-17, and has recorded six goals and 16 assists through 36 games this season. While his point total ranks him seventh among Atlantic blue-liners, his point-per-game average (0.61) puts him behind only Karlsson, Hedman, Rielly, and Shea Weber (currently injured).
He's also recorded the third-most points by a defenseman from that division since the beginning of 2015-16, with Karlsson and Hedman again leading the way.
Krug's game lends itself to three-on-three excitement, too.
Sergachev would by no means be a reach to replace his teammate. In 44 games, the 19-year-old has scored eight goals and added 18 assists, and his 26 points slot him fourth in the division (trailing Hedman, Karlsson, and Rielly), and 16th around the NHL.
He'll take on a bigger role for the Lightning with Hedman out of the lineup, and while he's been outperformed by Rielly and Krug (on average), he has proven to be a star performer perhaps sooner than expected. His presence would be a nice boost for Lightning fans.
(Photos courtesy: Getty Images)