Royals relief pitcher Kelvin Herrera is throwing a slider more often.
Royals relief pitcher Kelvin Herrera is throwing a slider more often. David Eulitt deulitt@kcstar.com
Royals relief pitcher Kelvin Herrera is throwing a slider more often. David Eulitt deulitt@kcstar.com

How Royals reliever Kelvin Herrera added a new pitch and transformed his arsenal

April 15, 2016 02:43 PM