[6] Greer contributed with 3 goals and 7 points in 37 games as the Terriers finished as regular season champions and claimed the Hockey East mantle to clinch a Frozen Four berth.

[8] Unable to produce offensively and un-willing to accept reduced minutes in a checking-line role, Greer opted to leave the Terriers after 18 games to further his development in his native Quebec, with the Rouyn-Noranda Huskies of the QMJHL on December 19, 2015.

Placed on the top scoring line in the post-season and serving as an alternate captain, Greer posted 22 points in 20 games as the Huskies captured the QMJHL Championship before losing in the Memorial Cup final.

[10] In continuing his unorthodox development path, Greer signalled the end of his brief QMJHL career to turn professional in signing a three-year, entry-level contract with the Colorado Avalanche on July 1, 2016.

[11] After attending his first training camp with the Avalanche and eligible to compete in the American Hockey League, Greer was assigned to begin his rookie season with affiliate, the San Antonio Rampage.

[13] Making a seamless transition to the professional level, Greer was leading the Rampage and all AHL rookies in scoring before he received his first recall to the Colorado Avalanche on November 12, 2016.

In a slow start to the season, Greer posted one goal and two points in 10 games with the Sound Tigers before he was traded by the Islanders, along with Mason Jobst, a 2021 first-round draft selection and a conditional 2022 fourth-round pick to the New Jersey Devils in exchange for Kyle Palmieri and Travis Zajac on April 7, 2021.

Leaving the Flames as a free agent, on July 1, 2024, Greer was signed by reigning Stanley Cup champions, the Florida Panthers, to a two-year, $1.7 million contract.