Diamondbacks starter Merrill Kelly tinkering with slider this spring training

Merrill Kelly doesn’t have too large of a reason to seek wholesale changes to his game.

There are 573 innings of work for the Arizona Diamondbacks on his resume since 2019. He’s coming off his best year as a pro, where he was efficient and effective to break the 200-inning mark with a 3.37 ERA and 1.138 WHIP.

But the right-hander sees room for a little addition to his game, not completely pleased with keeping it status quo despite leading Arizona’s starters, which included 2022 Cy Young candidate Zac Gallen, in swinging strike percentage and fewest pitches per plate appearance last year.

“I’m trying to implement a slider,” Kelly told Arizona Sports’ Wolf & Luke on Monday. “I think it’d be beneficial, in my mind, especially against right-handed hitters. I think I had a lot of opportunities to kind of put right-handers away.

“If I had a slider, I think it would’ve boded well.”

Kelly will have to report to camp for the United States for the World Baseball Classic before and during the March 11-15 event that will take place at Chase Field. So how much time and practice he’ll have to toy with a new tool remains to be seen.

He’s probably not starting from complete scratch.

According to FanGraphs, a handful of Kelly’s pitches in the past few years have registered as a slider. Baseball Savant has the grand total at six sliders thrown.

Those have made up 0.1% and 0.2% of his totals the past two years but has stood out as a mid-80s mph pitch that strays from the velocities that fall under his full repertoire of other pitches that includes a cutter, a sinker, a changeup and a curve along with the fastball.

If adding another more of that to the mix can keep batters off-balance, Kelly will be staying ahead of the opposition.

And that will keep him as the steady rotation presence he’s grown into for the Diamondbacks.

“In my mind, I want to go at least six innings every game,” he said of his season’s goals. “I think starting pitcher, that’s kind of a good gauge in my mind of what is a good game and what’s not. Innings to me are huge … I really scrapped my way to 200 innings (in 2022).

“I guess going into this season … if I had a goal, that would probably be the only one.”

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