 After becoming a restricted free agent in the summer, Gustavsson agreed a two-year extension with the Leafs on 15 April 2010, with an average salary of $1.35 million per year.In the following 2010–11 season, on 4 February 2011, he was sent down to the Toronto Marlies, the American Hockey League (AHL) affiliate farm team of the Maple Leafs, for a two-week conditioning stint.On 9 February, Gustavsson was pulled after the first period in a Marlies home game against the Connecticut Whale due to an accelerated heart beat.