2009-10: Paterson played for the Toronto Marlboros midget minor AAA team that competed in the 2010 OHL Cup. In 50 games with the Marlies, he had a 1.41 goals against and 15 shutouts. Paterson was 5-1 with 1 shutout and a 0.78 goals against in six games at the OHL Cup. He was selected by Saginaw in the second round (32nd overall) of the 2010 OHL Priority Draft.
2010-11: Paterson made his OHL debut with Saginaw as a 16-year-old and skated for the NOJHL's Soo Eagles Junior A team. He won a gold medal with Team Ontario at the 2011 U17 Hockey Challenge though he did not see any action. Paterson made 23 saves in a win over Belleville in his first start on October 23rd. In five appearances with the Spirit throughout the season he was 3-2 with a 2.97 goals against and .907 save percentage. Paterson was 10-1-2 with 2 shutouts and had a 2.95 goals against and .921 save percentage for the Eagles. In 15 NOJHL playoff games he was 11-4 with 3 shutouts and had a 2.42 goals against and .931 save percentage for the NOJHL champions. Paterson was named to Team Ontario but Daniel Altshuller of the Nepean Raiders started all six games.
2011-12: Paterson handled the bulk of the goaltending chores for Saginaw in his first full OHL season and was impressive in the playoffs for the Spirit. He appeared in 42 games during the regular season and was 18-21 with 1 shutout; posting a 3.42 goals against and .904 save percentage. The Spirit finished third in the West and reached the second round of the playoffs. The Spirit were the only team to beat league champion London in regulation in the playoffs – winning twice in the team's second-round six-game series. In 12 playoff games, Paterson was 6-6, with three of the losses coming in overtime, and had a 3.05 goals against and .903 save percentage. He was invited to the NHL Draft Combine and ranked third amongst North American goalies in Central Scouting's final rankings prior to the 2012 NHL Draft.
Paterson is an athletic goaltender who is at his best when he is playing within his abilities. He has the quickness to make a big save in the pinch, but also will challenge shooters. Paterson has leadership qualities, as well, making the players in front of him want to play well for him. Overall, he possesses the talent and desire to one day become an NHL goaltender.
Will return to the Saginaw Spirit of the OHL in 2012-13.