Robertson was sent to AHL Toronto on Saturday.
Robertson has eight goals and 19 points in 41 contests with the Maple Leafs this season while averaging 11:22 of ice time. His reassignment made room for Calle Jarnkrok's (hand) activation from long-term injured reserve. Teams can exceed the 23-man roster limit after the March 8 trade deadline, provided they remain compliant with the salary cap, which will give the Maple Leafs more roster flexibility past that point.