Robertson was placed on long-term injured reserve on Jan. 21 after suffering a knee injury in his regular-season debut due to a hit from Drake Batherson. Coach Sheldon Keefe originally estimated that the 19-year-old would be sidelined for about four weeks.
Sandin, 20, has appeared in one game with the Leafs so far this season. He recorded an assist against the Vancouver Canucks on Feb. 8 in five minutes of ice time.
Brooks has also appeared in one game for Toronto this season, scoring a goal against the Edmonton Oilers on Jan. 22 with 8:30 of ice time.
Marincin and Sabourin have yet to make their debuts with the Leafs so far this season. Marincin, 28, recorded one goal and four points in 26 games with the Leafs last season.
Sabourin, 27, spent the 2019-20 season with the Ottawa Senators, notching two goals and six points in 35 games.