According to the article below about last nights game and MT's usage of PK it doesn't seem like he played as bad as you seem to think he did.
http://www.habseyesontheprize.com/2014/4/2/5573676/pk-subban-michel-therrien-canadiens-coaching
The Canadiens had 23 even strength faceoffs in the defensive zone against Tampa Bay, and Subban was used for eleven of them. Eleven defensive zone starts in 9.8 minutes of time on ice, and yet when he was on the ice, the Canadiens were conceding one third of the shot attempts against that they were when he was off of it.
The fact is, Subban was absolutely incredible against the Lightning, and instead of riding that and looking for a spark to win the game, Michel Therrien indirectly called him out to the press, saying that the team was "too fancy" and "refused to chip the puck in".
That's right ladies and gentlemen, stop being good, dump and chase. That's the message from the coach of the Montreal Canadiens.
I think the way the article ends sums up the frustration that a lot of us feel about Subban's usage in general this season...
Eller needs to stop with the stupid penalities. I'm willing to have him be #4 center if he isn't a liability defensively and works hard, but when you are a big zero offensively(or at least south of Weise Moen Prust) you can't take lazy penalities 200 feet from your net.
I'm not saying Eller hasn't had some bad penalties this year, but from what I can remember, both his calls tonight were pretty much garbage, especially his 'holding' call where both his hands were on his stick...