D-backs Young Starters Learning to Throw Harder Sliders

The goal is to develop a slider, with more velocity and later break, that tunnels better with a four-seam fastball.

Some of the Diamondbacks' young starters have been tasked with throwing a harder slider over the offseason. These sliders typically will have more velocity and less overall but sharper and later break.

So far this spring, we've seen the results from that hard work. Blake Walston, Ryne Nelson and Slade Cecconi have discussed being able to throw a harder slider or cutter. Walston discussed being able to develop a cutter right around the 85 MPH range. Both Nelson and Cecconi have seen their slider velocity jump up two ticks this spring.

Pitching coach Brent Strom described the purpose of throwing a harder slider.

"We're trying to make the slider carry itself toward home plate for a longer period of time instead of bowing out. You're trying to keep it within a cluster, keep the pitches clustered as much as possible."

Having pitches that look the same coming out of the hand creates a tunneling effect for the hitter. Strom used the analogy of throwing a milk carton with the spout cut out to describe the tunneling effect. It starts as a block of milk but then separates in different directions. The longer it stays a block of milk for the hitter, the tougher it will be to make the right swing decision. That in turn leads to swings and misses or weak contact.

In the case of Nelson, who has made both his starts at Salt River Fields and has the largest sample size, he's thrown 47 fastballs and 23 sliders. His fastball has generated a whiff rate of 50% on 24 swings while opponents are hitting .083 (1-for-12) against the pitch this spring. The slider has generated five whiffs on 12 swings and opponents are 1-for-5. While a small sample size, it's an encouraging sign for a pitcher battling for a potential rotation spot and could make the Opening Day roster in some capacity.