Toronto Maple Leafs captain Auston Matthews continues to be sidelined by an upper-body injury that has not progressed as expected, forcing him to miss more time.

Matthews has sat out the Leafs' last three games with his ailment, related to a problem he's dealt with since the preseason. Toronto's star center did take part in the team's optional morning skate on Saturday - the first time he'd been on the ice in a week - but hasn't gone out again since then.

Coach Craig Berube said that's by design.

"[The injury] is just not getting to where it needs to get to," said Berube on Tuesday. "So, we're just trying to manage it and just trying to make sure when he comes back, he's good and 100 percent."

Berube said it was "not really" a setback so much for Matthews as just the team being cautious in supporting his recovery.

That echoes what Leafs' GM Brad Treliving said about Matthews' status during a media availability on Monday.

"[There's] no change [with Matthews] day-to-day," said Treliving. "We just want to make sure we get ahead of it and hopefully get it behind us once and for all."

Treliving characterized Matthews' status as "doubtful" for Toronto's game against Ottawa on Tuesday without providing any sort of timeline on whether he'd be ready to go Wednesday against Washington or even Saturday versus Edmonton.

"We'll just keep going down [the] path," said Treliving.

Matthews has been out of Toronto's lineup since appearing in a 2-1 loss to the Minnesota Wild on Nov. 3. He was subsequently placed on injured reserve and would have been eligible to be activated from there for Tuesday's game. For now, IR is where Matthews remains, and the Leafs will go for their fourth straight win without him on Tuesday.

"We're all trying to figure it out and work on it and make sure we get him back and this thing doesn't occur again over the course of the year," said Berube. "It's not something you want lingering on throughout the season, so we're trying to do our best to not allow that to happen."