Yep. Cant remember who was talking about it, maybe Cahill. He was of the opinion that on a fresh, pristine grass court that Feds odds go way up. Being a huge Fed honk, I am inclined to agree.
I am inclined to agree as well. As the tournament goes on you will see where the grass gets worn away, leaving dirt (in some areas of the court more than others, of course). The ball doesn't skid off the dirt as much as it does off the grass. The result is a higher bouncing ball, which, for all practical purposes, is a slower court.
The ball will still bounce much lower off the dirt than it will off hard court. You can pull up a youtube clip of various wimbledon finals and various us open finals and the difference will jump right out at you. But it will be bouncing higher than it was two weeks before at Day 1 of the tournament. And this helps Rafa and Djokovic, which of course hurts Fedsmug's chances.
But, to be fair, this phenomenon is nothing new. Indeed, the slowing down effect would have been more pronounced prior to 2002 when the grass was still a rye / fescue mix (it is now 100% rye, which is apparently a type of grass that does a better job of standing straight up, and thus is slower than the previous rye / fescue mix).
You raise a really interesting question, though. I'd like to know how much slower the courts get. And is it just in certain areas that the ball bounces differently? Because not all of the court gets worn out. If so, does that make the court non-uniform in the way it plays? It's the potential for non-uniformity that makes me think the slowing down effect is pretty minimal. Otherwise the players would have to deal with a court that played differently in certain areas than others. Which would make no one happy.
I wouldn't be surprised if it was Cahill. He is an excellent analyst.