Simmonds has played in just 3 games so far this season for the Leafs, but it's not because they don't want him to play - it seems like it's more because of the fact that he can't keep up and isn't as versatile as fourth liners like
David Kampf,
Zach Aston-Reese and, currently, Denis Malgin. Those guys are more defensively responsible than Simmonds, can contribute on special teams and have earned Keefe's trust. Not only that, but they are able to move the puck up the ice much quicker than Simmonds, who has lost a step or two at the age of 34.