According to Matthews, he got really sick after game two before taking a weird hit in game four that didn't help his condition, with the team thankfully keeping the series alive in his absence before falling in game seven. This was another tough break for the Maple Leafs and Matthews, who believed they finally had the team to make a deep playoff run, but here we are seeing exit interviews while round two of the playoffs roll on.
It appears as though no long term damage is expected from the issue, but given how violent of a sport hockey is, things like this will happen, so Matthews will be hoping for better luck in the playoffs next season as Toronto still aim to break their Cup drought.