Before being drafted into the NHL, Mascherin played for the Kitchener Rangers of the OHL, and put up great numbers, getting 80+ points in three straight season, with one of them being 100 points in 65 games. He was drafted in the second round (38th overall) by the Florida Panthers in 2016, but did not sign with the team and re-entered the draft in 2018. There, he was taken in the fourth round by the Dallas Stars.
Mascherin started his pro career with the Texas Stars of the AHL, where he spent three seasons. Unfortunately, for the Ontario native injuries kept him on the sidelines for two out of the three seasons with the Texas Stars.
Mascherin moved to Sweden, signing with Skelleftea AIK of the SHL. However, once again injuries reared its ugly head forcing him to miss much of the past two seasons.