Patrick Corbin threw his changeup just 1.1 percent of the time with the Arizona Diamondbacks last year. (John McDonnell/The Washington Post)

JUPITER, Fla. — Patrick Corbin made his share of changes heading into a career year with the Arizona Diamondbacks last season, when he went from a back-of-the-rotation starter to one of the most wanted pitchers in baseball.

He threw his two fastballs — a four-seamer that cuts a bit and a two-seamer that sinks — less frequently than he ever had. He upped the usage of his slider that soon would be considered one of the game’s best pitches. And he nearly ditched his change-up altogether, filling the void in his arsenal by introducing a looping curveball.

Now the new Washington Nationals starter may have another tweak on the way, even if it’s a small one. Corbin doesn’t want that change-up to completely go away in 2019.

“I always threw it, throw it in all my bullpens. We kind of just didn’t use it too much in games last year,” Corbin said Friday after pitching four innings in a spring training game against the St. Louis Cardinals. “But it was just something today we tried to throw more. I just want to get consistent with that pitch, kind of as another weapon.”

Here is how FanGraphs tracked Corbin’s pitch usage last season: 48.6 percent fastballs, 41.3 percent sliders, 9 percent curveballs and 1.1 percent change-ups. He went 11-7 with a 3.15 ERA, struck out just under 11.1 batters per nine innings and then signed a six-year, $140 million deal with the Nationals in December. The year before, in which he went 14-13 with a 4.03 ERA and struck out 68 fewer hitters, he threw his change-up 8.7 percent of the time and didn’t have a curveball officially recorded.

Developing the curveball while throwing far fewer change-ups was the most noticeable difference as the 29-year-old took the biggest leap of his six-year career. But he feels there is still room for his change-up. He wants to get it up to 5 percent this season — maybe even a bit higher — if only to give hitters something else to consider as he eases through his smooth windup. The tall left-hander does not throw particularly hard — his fastball hovers in the low 90s — and relies on deception and movement. A working change-up would provide more of both.

His results were mixed Friday, when he labored through a 30-pitch first inning before needing only 19 pitches to breeze through the next three. The same went for his change-up: He threw five of them, inducing four groundballs (including one that led to a rally-ending double play) and yielding a single to former Nationals catcher Matt Wieters.

“My first couple years in the big leagues I had success with it, and then kind of the last couple years went to the slower breaking ball,” Corbin said of the change. “So just trying to get more consistent with it, and in these games you can go out there and kind of work on it. But I’ll still stick to my strengths and do what I do well.”

An American League scout who has evaluated Corbin for a few years and watched his second start this spring sees a clear function for the change-up. The pitch is designed to appear like a fastball through the arm motion before coming out of the hand significantly slower. If the pitcher has it working, hitters will swing out in front of the ball. Corbin’s average four-seam fastball velocity was 91.3 mph last season, according to FanGraphs, while his average change-up velocity was 81.4. A difference of 10 mph should be more than effective. He also has that sharp decline in velocity between his slider and his curve, with the slider coming in last season at 82.1 mph and his curveball averaging 72.8.

Many starters throw change-ups regularly because their fastballs are the foundation of their pitch mix. But Corbin has two pitch-types from which to work — throwing fastballs and sliders with very similar frequency; employing a change-up and curveball would give him a complement for each. Corbin’s change-up naturally comes out like his fastball, the scout explained, and his curveball comes out just like his slider before changing speeds.

“Basically, his change-up is the change-up to his fastball, and his curveball is the change-up to his slider,” the scout said. “If he can throw all of that well, there is no way to know what’s coming as a hitter.”

The tentative plan is not for Corbin to make his change-up a prominent part of game plans. If he can gain more confidence in it across his last three spring training starts, he could wield it as what Manager Dave Martinez called a “visual pitch.” That means hitters see it, whether on tape or at the plate, and then have to consider it while Corbin fires his blend of fastballs, sliders and curves.

As effective as Corbin was last season, he can verge on predictable given his heavy diet of fastballs and sliders. Reincorporating a pitch, one he’s thrown throughout his career, is one simple, if slightly marginal, fix.

"Maybe one day another pitch isn’t working, " Corbin said. “So I think it’s always good to have.”

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