Pitchers without great fastballs tend to throw less of them. Old pitchers also tend to dial down their fastball usage as they age and throw pitches with more movement instead. The idea behind this is that deception is more valuable when a fastball loses its velocity, and pitches that move are better than pitches that are straight when velocity has declined. Do not tell this to J.A Happ, though, as the 38-year-old is throwing as many fastballs as ever.
Happ is 20th among 196 qualified pitchers in four-seam fastball percentage, with four-seamers making up 56.4% of his arsenal.