The article looks at the differences in the radar guns at different parks. Shields is going for a park which suppresses velocity to one which exagerates it. Quote: In terms of practical applications of knowing these effects, I can think of two interesting cases to watch in 2013. The first would be the case of James Shields, who will be shifting from a Tampa Bay home park that deflated four-seam fastball velocities of RHP by -0.16 MPH to a Kansas City park that inflated those types of pitches by 0.75 MPH.