Grzelcyk was born to play for the Boston Bruins.

A native of Charlestown, Massachusetts, Grzelcyk attended Belmont Hill School before spending two seasons with the U.S. National Team Development Program, after which he was selected by his hometown Bruins in the third round (No. 85) of the 2012 NHL Draft.

He would play the following four seasons at Boston University, including serving as captain as a junior and senior.

With the Terriers, Grzelcyk had 95 points (26 goals, 69 assists) in 125 games, was twice named to the NCAA East First All-American Team (2015, 2016), and was named to the NCAA Championship All-Tournament Team in 2015 after helping Boston advance to the NCAA championship game.

Grzelcyk signed a two-year, entry-level contract with the Bruins on April 1, 2016, and spent most of the following season with Providence of the American Hockey League, finishing with 32 points (six goals, 26 assists) in 70 games. However, he also made his NHL debut that season against the Pittsburgh Penguins on Dec. 14, 2016.

After opening the 2017-18 season with Boston, he spent the next six weeks in Providence before being recalled. Grzelcyk would earn his first NHL point in his return, against the New Jersey Devils on Nov. 22, 2017, and he scored his first goal two days later in a 4-3 win against the Penguins.

After opening the 2017-18 season with Boston, he spent the next six weeks in Providence before being recalled. Grzelcyk would earn his first NHL point in his return, against the New Jersey Devils on Nov. 22, 2017, and he scored his first goal two days later in a 4-3 win against the Penguins.

At 5-foot-9 and 174 pounds, Grzelcyk isn't going to be a physical force. But he's finding a niche as a smart, puck-moving defenseman who doesn't get overwhelmed by bigger opponents and as a result, he earned a regular spot in Boston's six-man rotation.

After helping the Bruins advance to the Stanley Cup Final in 2019, where they lost to the St. Louis Blues in seven games, Grzelcyk set NHL career highs in goals (four), assists (17), points (21) and games played (68) in 2019-20 before the season was paused due to concerns surrounding the coronavirus.

NOTES & TRANSACTIONS

• Hockey East All-Rookie Team (2013)
• Hockey East First All-Star Team (2015, 2016)
• NCAA East First All-American Team (2015, 2016)
• NCAA Championship All-Tournament Team (2015)