No, I think that is clear, but I also don't think it was a linear decline.
That 2nd Miami game on December 9th, I thought he ran and moved quicker than I'd seen him in a while. Hardly scientific, I realize, but I thought he looked different. His excellent offensive performance went largely unnoticed since he was widely blamed for giving up the last-second TD, which is debatable, but he caught 8 for 107 and a TD and was beating coverage all day. Running himself open like he used to.
I recall wondering if it was the warm weather or what, but even though he had some great contributions in the AFCCG and Super Bowl, after that game his movement skills seemed to me to revert back to the same sort of stiff, robotic look that we'd started seeing for a while and he caught only 5 balls over the next 4 games.
Of course, that doesn't prove anything either. We might have held him back just to get him off the radar to an extent.
It's strange, really. I'd love to know the specifics of what his injuries were but my gut feeling is he just keeps tweaking a chronic injury and can't get free from it. Back? Wheels? Both?
Whatever it was, it's a damn shame that he didn't get the kind of time that some of the other notable TEs did. Witten, those guys. He could have lapped the field if his body didn't break down.