The 20-year-old Matthews played nearly 20 minutes in Toronto’s 4-3 victory over the Penguins Saturday, but he collided with teammate Morgan Rielly with 2:48 left in regulation and appeared visibly shaken. He did return to the ice and finished the game, but hasn’t played or practiced since with an undisclosed “upper-body” injury.

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Addressing speculation Matthews suffered a concussion, Leafs coach Mike Babcock said he didn’t know whether Matthews entered concussion protocol.

“He said he was ready to go for the next shift, [and Matthews] seemed to be all right,” Babcock said to reporters following the contest with Pittsburgh.  

Matthews, however, was held out of the Maple Leafs’ 1-0 home win over Edmonton on Sunday and he will be out of the lineup Tuesday when Toronto plays the Flyers in Philadelphia. Babcock said Matthews is is traveling with the team and may be able to return Thursday or Friday, when the Maple Leafs take on Minnesota and Detroit, respectively.

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“He’s day to day, so I think he’s playing every day," Babcock said Tuesday. “Day to day is normally 10 days, but we’ll go day to day ‘til he’s ready.”

Matthews has 13 goals and 13 assists in 26 games this season. He also missed four games, all Toronto wins, with an upper body injury in early November.