ATLANTA -- How much of a challenge is it for Rockies right-handed pitcher Jon Gray (aka "Gray Wolf" on Players Weekend) to understand how his pitches move at home versus on the road? Put it this way: The different pitch action even created confusion for the latest technology.
Follow along:
According to Statcast™, in his first six starts this season, Gray's pitch mix and frequency was as follows: four-seam fastball, 55.9 percent; slider 26.1 percent; curveball 9.2 percent; two-seam fastball 6.7 percent; changeup 2.1 percent.
In the next six, he threw the four-seamer 55.2 percent of his pitches, slider 29.0, the curve 15.0 and two-seamer 0.9. It raised a question: What happened to the two-seamer, which tends to sink and tail to the arm side?
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Well, the Rockies' records had him at roughly 72 percent fastballs, 19 percent sliders, 6 percent curveballs and 2 percent changeups. The two-seamer didn't show at all. So more questions.
Then in Kansas City on Tuesday night, when he gave up three runs (two earned) on three hits, with six strikeouts, the two-seam fastball seemingly reappeared on several occasions in the data.
Was Gray simply adding and subtracting a pitch at will?
It turns out not. Gray said he can recall throwing a two-seamer three times all year: twice in a 10-strikeout performance at Arizona on June 30, and once in his home win over the Phillies.
Another look at Statcast™ data showed the majority of two-seam fastballs came during road games.

Bingo.
Gray's four-seam fastball moves to his glove side (outside to a right-handed hitter) and doesn't drop as fast. But sometimes that pitch dips and tails to the arm side -- like a two-seamer. This happens by design and at random.
"That's kind of the tough thing about making adjustments from home and road," Gray said. "You've got to think about where you're going to start off that pitch, because it's going to end up a little different when you're on the road. It's the same pitch."
"I can sink it if I want to, if I'm going down and away to a left-handed hitter. But if I'm going up and in, I don't want it to sink at all. That's how I get in trouble, if it runs back across the plate. So I just move my sights a bit to the left on the road with the fastball."
In Statcast™, by the way, the numbers have been adjusted. Even the two-seamers have been pinpointed.
Gray will enter Sunday's finale of a three-game set vs. the Braves with a lower ERA at home (3.00 in five starts) than on the road (5.72) -- a common phenomenon with 2017 Rockies pitchers. Gray credits pitching at a high altitude in Triple-A Albuquerque and on the road at Reno and Salt Lake City (he never pitched at Colorado Springs) with helping him pitch to the perimeters of the strike zone at altitude, where pitches don't move as much. He must harness the movement away.
Before the start against the Royals, Gray threw a bullpen session at Coors and at first was frustrated that his curve didn't drop far enough to make it a quality pitch. Then he remembered where he was.
"He said it out loud on the mound," pitching coach Steve Foster said. "'I'm not worried about it. When I get to sea level, that thing's dropping off the table.' And it did.
"The dynamic that we have is unique. It's a mental game and you have to be mentally tough."