Andrew Cashner trade: Marlins depending on Cashner’s improved slider

Part of what made Andrew Cashner an intriguing name in 2016 during the trade deadline was his most recent run of success since returning in July from a neck strain that put him on the disabled list. If the Miami Marlins are to get any value out of Cashner’s remaining half-season with the team and try and justify the gamble of sending away first base prospect Josh Naylor, it will be due to whatever is causing this improvement from Cashner.

Much of this has already been discussed by August Fagerstrom of FanGraphs a week ago, but it warrants repeating: there is some evidence of change in Cashner’s game since returning from the injury. Part of it is the uptick in fastball velocity, with his “two-seam” fastball up half a mile per hour as compared to before. Overall, however, Cashner’s velocity has been down 1 mph since last season, and that is not an encouraging sign. He still throws mid-90’s heat, but now that heat is at 95 rather than 96.

A bigger part, however, of this most recent conversion to whiff-inducing Cashner is his use of the slider. August noticed it through his first four starts after the DL stint.

The usage is way up. The velo is way up. The confidence is way up. He threw it 6% of the time to lefties before, and 13% with two strikes. These last four starts, lefties have seen it 22% of the time, overall, and 40% once Cashner gets ahead. Used to be that the slider was Cashner’s out-pitch against righties, and he stuck with the fastball against lefties. Now, he wants to end every at-bat with the slider.

Before the DL stint, Cashner was using the slider around nine percent of the time, less so than his changeup. It was traveling 86.8 mph on average. However, it seemed as though Cashner felt uncomfortable throwing it. He certainly is not uncomfortable throwing it now, as he has upped its usage to 28.5 percent since the disabled list stint. He is throwing it about half the amount he has thrown his fastballs, and it has worked.

The slider looks better than it was before. Hitters are swinging less, but they are whiffing at near equivalent amounts and Cashner is not getting as crushed on them. Far more importantly, however, is how often he is using them not only against righties but against the other half of the platoon as well. Before this season, Cashner was using his slider 20 percent of the time versus righties and just 13 percent of the time versus lefties since 2014. Since the injury return, he has cranked up his usage against both sides, throwing it 36 percent of the time versus righties and 21 percent versus lefties. The pitch has not faltered against southpaws as well. Lefties have swung past it on 48 percent of swings, and they are hacking at 52 percent of those pitches.

This success with the slider is also backed up by what the pitcher himself says.

"I think that's what I struggled with this whole season," he said. "I've messed with probably 10 different [slider] grips and finally got back to where I was last year with it and finally staying behind it."

Cashner’s slider may be his best weapon and now he is using against both sides of the plate. This uptick has come almost entirely at the expense of his two-seam fastball, and therein lies the concern. It should be noted that while the slider usage has been up this month, his ground ball rate has dipped to 38 percent after staying around his career norms in the months before the injury. Subsequently, Cashner has had a hard time with home runs all year, but it was worse this past month, with seven homers allowed all month. Still, even with the decrease in grounders, it would be highly unusual for any pitcher pitching otherwise as well as Cashner did in July to give up seven homers again; his xFIP, which corrects home run rate by ground balls allowed, put him at an expected ERA of just 3.75.

Cashner will not solve all of Miami’s problems, but this renewed work with the slider is something new that logically can lead to success and is related to what at least sounds like some mechanical change. If this slider continues to work well, Cashner could return to being the mid-rotation starter he was from 2014 to 2015 rather than the shell of a pitcher he looked like earlier in the year. It is no guarantee, and not all of these changes are real by any means, but there is something new and not simply a cherry-picked five-start sample of success.