Matthews does well when the puck is cycled behind the net. Get Marner away from Matthews. Try Nylander-Tavares-Marner
If Matthews has another big night and then goes stale when Marner comes back. It's time for Keefe to stop worrying about individual players.
For a coach that talks about trying different things in his post games, it really is surprising Nylander and Marner don't get many looks together. Maybe Matthews wouldn't like that? Sure Matthews can put up points with anyone, but having an elite playmaker does help.
With Nylander elevating his game maybe you give him one more look at center.
Jt-Matthews
Nylander-Marner
It could very well fail miserably, but I can't say I wouldn't be interested in seeing it.