Selected by the Boston Bruins in the fourth round (No. 121) of the 2011 NHL Draft, Ferlin drew notice in junior hockey by scoring 25 goals and 73 points during the 2010-11 season for Indiana of the United States Hockey League. Bruins scouts liked Ferlin's size (6-foot-2, 217 pounds), his ability to play along the boards and in traffic and his toughness in front of the opponent's net.

Having already committed to Cornell University, after being drafted Ferlin joined the Big Red for the 2011-12 season. He had eight goals and 21 points and was named both the ECAC and Ivy League's top rookie.

Ferlin turned pro in the summer of 2014 and, after attending Boston's training camp, was assigned to the Bruins' American Hockey League affiliate in Providence.

He spent most of the 2014-15 season with Providence, but did play seven games with the Bruins. Ferlin made his NHL debut Feb. 20, 2015, playing 10:33 against the St. Louis Blues.

March 22, 2015, marked another highlight for the Jacksonville, Fla., native: After being a healthy scratch in eight consecutive games, he was inserted into the lineup for a road game against the Florida Panthers. Ferlin's parents and a group of friends made the five-hour drive from Jacksonville to Sunrise, Fla., for his seventh NHL game.