Garrett Whitlock explained how using a third pitch more often has helped him stay a step ahead

For Red Sox relief pitcher Garrett Whitlock, the 2021 season has already been a roller-coaster ride.

After not allowing a run in the first month of his Major League career, Whitlock, 25, experienced comparative struggles in May (with a 4.03 ERA as batters hit .318 against him).

Flash forward to June, and Whitlock is back to dominating, posting a 0.66 ERA in the month so far.

Granted, ups and downs are a built-in feature of a 162-game season, but in Whitlock’s case, there’s an added dimension that helps to explain his readjustment to hitters’ earlier adjustment.

As Whitlock recently explained to WEEI Red Sox reporter Rob Bradford, his increased usage of a slider has made all the difference. As…