To be fair to Tavares, he has no linemates right now. Marner was good for him but Marner and Matthews are better together. Nylander is not an ideal linemate for Tavares. I dont think people realize the anxiety Nylander creates for his linemates, based on him being an enigma from game to game.
To my eyes, it looks like Tavares is the one who is out of sync right now and nothing to do with either Kerfoot or Nylander. To isolate the problem, it's maintaining speed while carrying the puck which creates two other problems:
When Tavares receives a pass or gets to a loose puck, he has that stop up, post up tendency and starts stickhandling stationary while the other team kind of swarms him in open ice. In the past, we'd see him try to compensate by doing his little aggressive zig zags and hard evasive slalom style maneuvers, use his lower body strength to fight off the opposition before he's entirely swarmed but he's not as aggressive with that this year.
This means he's basically stickhandling while at a standstill with two or three checkers draped all over him, which forces him to take a low percentage slap shot, throw something on net, make a broken play, or turn over the puck altogether. So the range of possibilities is often distributing the puck in chaotic and unpredictable ways to his teammates or the opposition.
In terms of statistics, it's never a problem with him, but has a way of masking over a lot of inconsistent play. He has 2 GP 1 G 1 A 2 PTS in the Ottawa and Montreal games that just passed, which is a PPG and looks pretty decent from distance. But if you actually watched both of those, his declining ice time and how he's basically being force fed a scoring chance in a 7-3 blow out or getting a second assist in his own zone on the 5th goal in a 5-3 win, it's not so great.
At the end of the day, if we get out of the North Division and make a long run we need Tavares to do something, anything that don't waste the season that the Big Line is having. If he can give us $7 million hockey and guys like Thornton, Spezza, Simmonds and company stay strong we will be in good shape. But right now, it's just a painful process to watch.