It feels like every great pitcher has a signature pitch. Nolan Ryan threw absolute heat. Randy Johnson paired his heat with one of the most devastating sliders any generation has ever seen. You utter the name Mariano Rivera, and inevitably it's closely followed by the word "cutter."

Oakland Athletics' ace Sonny Gray and his curve may not have been at the aforementioned level, but when he was drafted and as he was coming up through their system, it was certainly considered his core offering. When discussing which pitching prospect would have the biggest impact on the 2013 pennant races,'s Jim Callis named Gray, saying, "his hard curveball is his signature pitch."

This belief certainly wasn't in the minority. Prior to the 2012 season, Kevin Goldstein wrote of Gray:

His curveball is a plus-plus offering that many scouts consider among—if not the best available—in the 2011 draft.

And the praise continued for Gray's curveball as he arrived in the big leagues. Carson Cistulli delivered seven similes to best describe the breaker. Early in the 2013 playoffs, one author named the best pitches of the postseason and right there alongside Jon Lester's cutter and Francisco Liriano's slider was Gray's curve. The pitch was hyped from the moment he was drafted and the kid was delivering with it as he rose to the bigs.

As Gray has emerged as one of the best arms in the AL over the last two years, with this season being his true coming-out party, the easy assumption is that he's done so by riding his devastating curveball along with his mid-90s heater. But shockingly, Gray has found success in the majors by straying from the pitch that helped build his name and get him drafted 18th overall in 2011.

"I've obviously added pitches here and there throughout the last couple years," Gray told me. "I think I've started throwing more four-seam fastballs. It has a little bit of a cutting action, but it's just how it comes out from my four-seam. Mostly it's just trying to be more aggressive and not necessarily try to strike everyone out. Just kind of get early contact and get deep in the game. It's just something that I've really learned to do over the last couple years."

That early contact is the key for Gray and it's something both he and his pitching coach, Curt Young, believe is key in taking his game to its current Cy Young level.

"It's the good, fundamental thought process of getting ahead with movement down in the zone," Young said. "He's been real good with both his breaking balls, he'll mix in changeups at times. He's been through periods with higher strikeouts and he knows that's going to take him to a higher pitch count and get him out of the game early. So he understands that early action and early outs means he'll get to pitch deeper into the game."

In his rookie season, Gray struck out 26 percent of the batters he faced and over the last two seasons that number has dropped to just above 20 percent. So with the mindset of going for more contact to reduce his pitch count, the strikeouts have dropped. But that started last year. As we see above, the pitch mix has changed quite a bit this season, so the natural question becomes: Why has this pitch-mix led to Gray taking another step in his development?

While both the strikeout and groundball rates have dropped in 2015, we can point to a career-low 7 percent walk rate. But that's just one factor in Gray's improvement. A deeper look tells us that Gray is getting opposing batters to swing at his offerings at a career-best rate (47 percent), particularly at pitches in the zone (64 percent). But none of this tells us why Gray has gone away from the curve in favor of the four-seamer and slider. To understand that, we have to really know Gray's mentality.

"In college you can throw a lot more breaking balls and go for strikeouts," Gray said. "But I just try to shoot for the middle of the plate and down now. Just put the pressure back on the hitter. It obviously doesn't always work out like that. But that's kind of my philosophy, just trying to throw fastballs toward the bottom of the zone and get guys to hit balls on the ground early."

Pounding the lower half of the zone was an aspect of the game that Gray struggled with in the minors. As Jason Parks wrote prior to the 2013 season:

To remain a valid rotation prospect, Gray will need to refine his command and work lower in the zone. Because of his limited height, he has a tendency to elevate the ball, losing movement and command, and often putting the ball on a tee for hitters.

Gray admitted to me that being under six feet tall can be a disadvantage for a pitcher, but he believes he found a way to rectify any issues that may arise from his stature. "I think the most important thing is just trying to throw the ball downhill," Gray said. "I think that's why they say short pitchers can't do that. But if you can just figure out a way to create some angle on the ball, try to throw it at the bottom of the zone with any type of movement, then you can have the same effect as someone who's 6-foot-4. Yeah, you may have to do some things a little bit different, but who's to say you can't do it?"

Young echoed much of Gray's sentiments and added that he has as high an arm angle as any sub-six-footer and creates an immense amount of energy going down the slope. All that leads to Gray being able to pound the lower half of the zone with his fastball this summer.

If we take a look at Gray's fastball usage in 2014 and compare it to this season, we see a clear pattern change.

We already knew he was throwing the four-seamer more often this season, but it's obvious that, as Gray said, he's pounding the zone middle and down with the heat. It's a perfectly reasonable approach; it's rare that a pitcher would want to consistently go up in the zone with his fastball. And it's exactly that mindset that has led to Gray wandering from his curveball.

"I haven't really thrown a lot of changeups until the last couple months," Gray pointed out. "So if you don't have something that looks like a fastball—and a curveball doesn't necessarily look like a fastball coming out—you just have to have something that looks like a fastball for as long as possible, and a slider kind of has that effect more than a curveball."

A curveball can look like a fastball, but certainly not a low fastball. It was never that Gray was unable to throw his fastball down in the zone; he just believed that with his repertoire he needed to be higher in the zone with the pitch. As Ryan Morrison pointed out at BP Boston, Rich Hill has taken to this method, the same one that made Ted Lilly effective:

By throwing high with his fastball, the high "hump" of Lilly's curveball stayed in the same general plane for a longer period of time; had he thrown fastballs primarily at the bottom of the zone, they would have been distinguishable right away — and his fastball and his curve would both look like they had flashing lights on them.

Gray understood that to ensure the opposition couldn't immediately identify his curveball, he needed to stay up with his fastball. However, that's a dangerous way to live. For pitchers like Lilly and Hill, it's likely the only way they can find success. It works for them, but if they make even the slightest mistake with that fastball up in the zone, the results can be disastrous.

Gray, on the other hand, isn't limited to just one breaking ball. While his curveball had gotten him to where he is now, his slider is pretty impressive as well, and using it allows him to go down in the zone with his four-seamer, inducing early—and often weak—contact, keeping his pitch-count down, and, in the end, letting him go deeper into games.

"Sometimes (having so many plus pitches) takes a scouting report and it throws it for a loop," Young said. "They expect certain things and Sonny can do different things than what other teams are used to seeing him do."

It's not uncommon to see pitchers evolve as their careers go on. Injuries or ineffectiveness often force them to dump a pitch that they may have relied upon heavily in the past. However, neither was the case with Gray; the young righty dominated in his first go around the bigs and actually improved in his first full season. However, he wasn't satisfied with his place in the baseball world and new he could elevate his game with a few tweaks. It's rare to see a pitcher willingly go away from his "signature" pitch and actually improve, but that's exactly what Gray has done. He may never go down in history for one great single pitch, but that won't stop Gray from trying to become one of the better arms of his generation.

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Nice article. Thanks!
One of my favorite pitchers to watch. What's incredible about his slider is that it's already one of the best in the game. According to Fangraphs' pitch values, his slider is 9th best in value per 100 pitches among starters.

Maybe even more impressively, his fastball, slider, and curve all rank in the top 11 for the same metric among all qualified starters. Only three other pitchers have that kind of killer repertoire with three double-plus to elite pitches:


Those are three names any pitcher would want to be mentioned with.
Missed one, Greinke is in that group as well.
So, what happened to him when September started? is it just fatigue that made his ERA explode?