https://www.profootballfocus.com/blog/2013/03/08/performance-based-value-tight-ends/ Mainly the injury issue. Caveat emptor.
IMO, there are a lot of red flags on Dustin Keller. In just looking at the numbers, since 2009, Dustin Keller has consistently been among the most targeted tight ends in the NFL relative to his team's overall targets. He's consistently received more than 20% of his team's targets, which tells me that he was one of the main receiving threats on the team. However, up until this season, his catch rate has hovered around 54-58%. This past year, his catch rate was 77%, but this may be due to SSS since he only played in 8 games. The same thing goes for his yards per target. He's consistently been in the 6.6-6.8 area, but this past season, he was at 8.8 yards per target.
I'd be faking injuries too if I had Sanchez as my QB... doing this to me: [video=youtube;CbMBW7GmX1E]http://www.youtube.com/watch?v=CbMBW7GmX1E[/video]
Yup! That looks like what happens when the 3:35 PM Freight meets the milk truck! Lucky he didn't disappear entirely after that! Or maybe, it's a miracle that Sanchez didn't disappear from a visit the guys Bob Marino said ought to visit Osama.