I'd like to see some of the more Pitch F/X oriented people take a stab at this, but I was just going through some of Tim Lincecum's Pitch F/X results from the past few years and have a few observations on things that are happening and why he may be having some more difficulties this year.

• His velocity is dropping.  His yearly average fastball speeds are 93.6, 94.0, 92.4 (90.0), and 91.2 (91.1).  The Parenthesis are classified as two seamers, which he seems to be throwing more this year.  Or perhaps they are finally being classified as such.  Either way he is losing speed, almost 3MPH since his first full season. 
  
• His change up speeds are staying steady at 83.2, 83.3, 83.1, and 84.0.  He's getting less separation on the speeds, which is making the fastball easier to catch up with.
• He's getting less movement on his fastball.  His fastball horizontal movement has been 3.5, 2.6, 3.1, and this year 0.3.  The vertical movement is virtually the same, he's hovered around 10 his whole career, but his fastball is a lot straighter this year.  His change has around the same movement, 3.8, 2.7, 3.2, and 3.0, while having less break vertically.
  

Anyone able to take a stab at illustrating these a bit better?  Or presenting other explanations?  These are just a few things I noticed when going through some of FanGraphs Pitch F/X Data.  It seems perhaps it's been easier to pick out his fastball since it has different movement than the change this year.  Is this supported in other data?