Maple Leafs forward Auston Matthews remains questionable to play in Game 5 of Toronto's first-round Stanley Cup playoff series against Boston on Tuesday. Toronto faces elimination while trailing the Bruins 3-1 in their best-of-seven series.

Matthews -- who has been fighting a lingering illness for over a week -- skated less than 10 minutes prior to the Leafs' optional morning skate at TD Garden on Tuesday. He went through some light drill work with Toronto's assistant coaches and departed before the full session got underway.

It was the first time Matthews had been on the ice since being pulled by Toronto's doctors before the third period in Game 4 on Saturday. Coach Sheldon Keefe said it would be the doctors again deciding whether Matthews was healthy enough to suit up for Game 5.

"He's working through things to try to make himself available to play. No determination at this time," Keefe said. "We'll see how the rest of the day goes."

Keefe declined to comment further when asked if there was anything else Matthews was dealing with beyond just the illness.

"I've already answered too many questions on the situation," Keefe said. "At this time of the year, we're not going to answer much else."

Matthews played through his sickness in Game 3, a 4-2 Leafs' loss, and stayed in through the first 40 minutes of Toronto's 3-1 defeat in Game 4. The Leafs' top center had his best outing in Game 2, tallying all three points he's earned this series, including the game-winning goal.

If Matthews isn't able to play, Keefe plans to move Max Domi to Matthews' top line spot and elevate William Nylander to the team's second line. Domi would also take Matthews' spot on the Leafs' sputtering power play, which is 1-for-11 in the playoffs.

Toronto is eyeing a change in net as well for Game 5, projecting to go from Ilya Samsonov to Joseph Woll. Samsonov has started all four games against Boston so far but was replaced by Woll for the third period in Game 4 after Samsonov allowed three goals on 16 shots. Woll made five saves in relief of Samsonov.

The 25-year-old had a solid regular season primarily backing up for Samsonov, collecting a 12-11-1 record with .907 SV% and 2.94 GAA. Woll got his first taste of NHL postseason hockey last year when Samsonov was injured in the second round against Florida and Woll took over the crease, posting a .915 SV% and 2.43 GAA.

Woll did not participate in the Leafs' skate -- and Samsonov did -- to indicate Woll was the likely starter.

"For a young guy he's pretty steady," Leafs forward Ryan Reaves said of Woll. "I think he's excited to get in there and do his thing. We're a confident bunch when he's in the net."

Keefe stressed after Monday's practice the importance of Toronto improving on special teams and goaltending if they were to stay alive for Game 6. Boston's halted their goalie rotation and stuck with Jeremy Swayman for three of the four games, and Swayman's been excellent (3-0-0, .956 SV%, 1.34 GAA). The Bruins' power play has also given the Leafs' fits at 6-for-13 in the series.

Boston had both Brad Marchand and Danton Heinen back at their own morning skate Tuesday after the veterans sat out Monday's session for maintenance. Coach Jim Montgomery had hinted at a possible return for injured skaters Derek Forbort and Justin Brazeau as well but wasn't tipping his hand on Tuesday.

"Might be some lineup changes," Montgomery said. "Or, might be exact same lineup [as Game 4]."