Scrivens started the 2010–11 season with the Reading Royals of the ECHL, the Maple Leafs' second tier affiliate. He played in 13 games with the Royals, winning 10. For his efforts he was selected to represent the Royals in the ECHL All-Star Classic. His strong play at the ECHL level, and injuries to other goalies in the Maple Leafs systems, earned Scrivens two separate callups to the Toronto Marlies of the American Hockey League (AHL), one in November and one in February. Scrivens was one of two goalies on the Marlies Clear Day roster announced on March 8, 2011, meaning he would be spending the remainder of the season at the AHL level, barring injury or suspension.
The Maple Leafs re-signed Scrivens on July 1, 2011. He was called up to the NHL as of October 24, 2011, in an emergency situation. After serving as backup for the previous games, he made his first regular season start on November 3, 2011, in Columbus against the Blue Jackets. In that game, he recorded his first career win and stopped 38 shots in a 4–1 game. As the NHL resumed play after the 2012–13 NHL lockout, Scrivens became a full-time NHL goaltender for the first time, serving as the backup to James Reimer, starting Toronto's first two games. Scrivens recorded his first NHL career shutout February 16, 2013, in a 3–0 victory over the Ottawa Senators.
