Toronto Maple Leafs forward Auston Matthews has been placed on injured reserve retroactive to December 20, the team confirmed Tuesday.

Matthews is dealing with an upper-body injury and is eligible to return whenever he’s deemed ready — due to the IR designation, he would’ve been eligible as of December 27, and the move allows the Maple Leafs to free up a roster spot. Matthews will miss his fifth consecutive game, but he participated in Monday’s practice and Berube indicated that he’s optimistic about his progress.

“He skated yesterday and had a good skate. I’m glad he’s out there,” Berube said Tuesday morning. “It’s good to see him out there out with us at practice. Really, we go from there and see if he progresses tomorrow, and see if he’s out there in practice tomorrow with us.”

Pontus Holmberg and Oliver Ekman-Larsson have been ruled out of Tuesday’s game against the New York Islanders due to illness, and it affords the Maple Leafs some further flexibility in the event that more call-ups are needed. Berube said he’s moving Kampf up to the lineup, and placing Connor Dewar as the fourth-line centre.

Ekman-Larsson has recorded one goal and 13 points in 37 games, while providing a physical presence on the Maple Leafs’ revamped blue line.

David Kampf will be moved up into a top-six role as a result of Holmberg and Matthews’ absences. Kampf has recorded one goal and five points in 24 games this season, while featuring on the penalty kill.

Marshall Rifai has been called up from the AHL’s Toronto Marlies in a subsequent move. Rifai was previously called up by the Maple Leafs this season but did not play. The 26-year-old has recorded two goals and four points in 24 games with the Marlies this season, and was widely considered a rising talent within the organization during training camp.