I believe him.
GSP started to show his frustrations with the media work and obligations in the run up to the Koschek fight and showed it again for the Shields fight. Whilst i wouldn't doubt GSP's integrity i do wonder if year and a half off was truly needed to recover from the injury or if it was recovery plus extra down time.
Three fights left? i believe him.
Michael Bisping defeats Cain Velasquez via KO (Spinning Heel Kick and Flying Uppercut) at 00:07 of Round 1.