The bench boss confirmed Matthews' wrist was bothering him as Wednesday's 2-1 win over the Calgary Flames progressed, and that the superstar forward didn't take the first faceoff in overtime because he wasn't comfortable doing so.
"We'll see how he is. (The training staff) will continue to take care of him and monitor it," Keefe said. "We don't think it's anything more at this point than what he's been dealing with virtually all season."
Matthews, who leads the NHL with 18 goals, assisted on both of William Nylander's markers against the Flames on Wednesday.
In doing so, Matthews became only the third player in Maple Leafs history to notch a point in at least 18 of his first 20 contests in a season, joining Babe Dye (19 in 1921-22) and Darryl Sittler (18 in 1975-76).
The 23-year-old center put together a pair of stellar scoring runs earlier in 2021, racking up 11 goals over 10 games from Jan. 16 to Feb. 8 and amassing another seven across four contests from Feb. 15 to 20. He's averaging nearly 22 minutes of ice time.
It's unclear if it's related, but Matthews sat out last season's on-ice All-Star events to receive treatment for an ongoing wrist condition. He did attend the festivities.