Jon Gray Is Becoming the Best That the Rockies Have Had

Although it’s not yet completely certain, it looks like the Rockies are going to earn a trip to the playoffs. Should they get there, they’re going to need someone who looks like an ace. And, you know what, even if the Rockies somehow miss the playoffs, there’s still going to be more baseball, in 2018 and beyond. In those years, the Rockies are going to need someone who looks like an ace. Even in this era where starting pitchers have slightly diminished importance, there’s no substitute for a No. 1. Every team could use one; every team badly wants one.

The Rockies might thank their lucky stars for Jon Gray. Not that it’s all been luck, of course — the Rockies drafted Gray in the first round, and the Rockies developed him. But, with pitching prospects, anything can happen, for almost any reason. There would’ve been countless opportunities for Gray’s career to veer off the tracks. Still could, I suppose. Nothing’s for sure. But where Gray is, now, a few weeks shy of his 26th birthday — he seems to be becoming the best starting pitcher the Rockies have ever had.

Yes, I know, that might not mean very much. The Rockies don’t have a history of possessing top-level starters, because the environment has tried to make pitching impossible. Calling Gray maybe the best the Rockies have had doesn’t pack the same punch as if this were the Yankees. But the Rockies have been around for 25 years. They’ve had a lot of pitchers. Let’s fly through some tables. For all of these, I’ve set a season minimum of 100 innings. Here are the top five Rockies starter seasons, by ERA-. In case you’ve forgotten, ERA- is scaled such that the average is 100. An ERA- of 90 would mean the pitcher was 10% better than average. Okay!

Right, of course, Marvin Freeman. Who could forget about Marvin Freeman? Gray shows up here in fifth, but then, we also know that ERA is kind of noisy. Why not switch to FIP-?

Would you look at that? The natural comparison is to Jimenez. Jimenez had some incredible seasons, before the downturn. Gray still holds an edge in here. We can go further, looking at xFIP-. A disadvantage is that this only goes back to 2002, but we can still work within that window.

Gray, first place, beating out Jimenez. Also beating out himself, from last season. Five points here is a healthy edge. For one final small table, I’ll show you the average of ERA-, FIP-, and xFIP-. Again, this goes back only 15 years, and not 25.

It’s not Jon Gray by a mile, but first place is first place. The one thing Gray hasn’t proven is that he can keep this up even longer than he has. Jimenez, for example, is in there for back-to-back seasons. So maybe peak Jimenez is still the best starting pitcher the Rockies have had. In that case, all Gray should need is time. He’s already found himself on the right track.

We’ve been conditioned to know what to do with statistics posted by Rockies hitters. We don’t so much extend a parallel courtesy to Rockies pitchers, who have to pitch in a nightmare ballpark half of the time. Rockies pitchers, therefore, are less often noticed, because analysts love to focus on strikeouts and walks, and no ballpark is more cruel to a guy’s K-BB%. Even given all of the obstacles, Gray has put up numbers that sparkle on the surface. And, for the sake of reference, this year there have been 132 pitchers who’ve cleared 100 innings. Gray is tied for the seventh-lowest FIP-. He’s two points ahead of one Clayton Kershaw. He’s dead even with one Max Scherzer.

Gray, even last year, was statistically intriguing. Despite the strikeouts, though, his ERA still wound up closer to 5 than to 4. A step forward has been achieved. Here’s one easy way of understanding it. For each of the last two years, I calculated the difference between each pitcher’s in-zone swing rate and out-of-zone swing rate. Here is the plot of 2017 vs. 2016, with Gray highlighted in yellow.

Gray has improved by 8.3 percentage points. No other pitcher has improved by more. This hasn’t been about Gray getting hitters to chase. The chase rate has stayed essentially the same. But when Gray threw a pitch in the zone last season, opponents swung 66% of the time. When Gray has thrown a pitch in the zone this season, opponents have swung 58% of the time. He’s gone from having one of the higher rates to having one of the lowest.

It’s easy to understand how this would be beneficial. Pitches in the zone are strikes, yes, but they’re the easiest pitches to hit. A pitch in the zone that isn’t swung at is a free strike, automatically. No risk of other damage. Jon Gray has been finding more called strikes, and fewer swings. That’s not how he’s improved; it reflects how he’s improved. Gray now just has a fuller, more deceptive repertoire.

He has the fastball.

He already had the fastball. He has the slider.

He already had the slider. Now, more than before, Gray has a useful curve.

When Gray first showed up on the scene, he was a fastball/slider/changeup pitcher. Now he’s effectively a fastball/slider/curveball pitcher. And while he threw curveballs in 2016, too, this year’s curve is so much sharper. Consider that his in-zone swing rate on curveballs has dropped 11 percentage points. Meanwhile, his out-of-zone swing rate on curveballs has increased 14 percentage points. The curveball has become more of a weapon, and it’s making Gray’s other pitches better. Batters can no longer sit on one breaking ball, nor can they just guess between slider and heat.

There’s one more thing I’d like to mention. Gray isn’t just figuring out how to pitch in the majors. He’s also figuring out how to pitch in Colorado, and how to pitch elsewhere. A season ago, Gray threw the same rate of fastballs, whether he was at home or on the road. This year, his home fastball rate is higher than his road fastball rate by eight percentage points, those extra pitches coming at the expense of the breaking balls. The results? Gray’s ground-ball rate at home is 13 points higher than what it is on the road. That’s the biggest such difference in baseball. And Gray’s K-BB% on the road is more than five points higher than what it is at home. That’s one of the biggest such differences in baseball. Jon Gray is still Jon Gray anywhere, but at home, he’s more oriented toward getting the grounder. Away from Colorado, Gray looks more like a regular ace.

Jon Gray has his third pitch. He obviously has the arm strength. He’s figuring out how to pitch in the majors, and he’s figuring out how to pitch in the majors’ worst pitching environment. If there’s one thing Gray’s missing, it’s a longer track record of success, but that’s currently in development. Somewhat quietly, Gray has blossomed into one of the better starting pitchers around. He’s becoming maybe the best starter the Rockies have ever had, and there’s no better arm around which these Rockies can rally, be it now, be it in the future, or be it both.