Previewing Jon Gray: postseason edition

The Colorado Rockies punched their ticket to the postseason this past Saturday, securing the second National League Wild Card spot with the Brewers’ loss against the Cardinals. On Sunday, the team confirmed that right-hander Jon Gray will get the ball against the Arizona Diamondbacks in the one-game wild card game on Wednesday.

This is exactly how the Rockies must have imagined it when they picked Gray with the third overall pick in the 2013 MLB Draft. He was their pitcher of the future, the man who would start important games for them when the time came. Likewise for Gray, this is the most important start of his young career.

The 25-year-old is in the midst of his second full season with Colorado, and he quickly catapulted himself to the top of a rotation that lacks a star veteran starter. In short, the Rockies don’t have an established ace (de facto or otherwise) but Gray could eventually fill that mold in the years to come.

That, of course, isn’t discrediting the success that he’s had in his career thus far.

In 20 starts this season, Gray pitched to the tune of a 3.67 ERA and a 112-30 strikeout-to-walk ratio (3.17 FIP; 3.45 xFIP) in 110 ¹⁄₃ innings pitched. Among starters with at least 100 innings pitched, Gray’s park- and league-adjusted ERA- of 73 was tied for the 17th-best in the Majors; his FIP- of 69 was tied for eighth-best. In all, he was worth 3.2 fWAR.

Gray’s biggest test comes Wednesday, when he faces off against Zack Greinke and the Diamondbacks.

“I think I’ve been taking a step forward with each game this season, so I’m ready to build on that,” Gray told the Denver Post. “I’ll be ready.”

One of Gray’s best starts of the season came against those very Diamondbacks at Chase Field no more than three weeks ago, when he pitched seven strong innings, allowing two runs on seven hits while striking out 10.

And, one might think that Gray has the opportunity to be his best self pitching away from hitter’s paradise from Coors Field. In fact, though, this might not exactly be the case.

Gray’s numbers at Coors Field are actually objectively better than those when he’s on the road. He has a lower ERA and holds hitters to a worse OPS in high-altitude Denver than he does anywhere else. Surprisingly, Coors hasn’t caused his home runs allowed per plate appearance to spike.

What does this mean for the Wild Card game? In reality, it means next-to-nothing, considering the game is in Arizona. We can’t possibly figure out how Gray will pitch on any given night with pressure he likely has never faced before while pitching in the Majors. However, we can use historical data to figure out how certain conditions have affected him.

Lucky for us, playing in the same division as the Diamondbacks gives Gray more starts against them than just about any other team. He has made two career starts at Chase Field, both coming this season. He allowed a home run in both of said starts; this is significant because he only allowed 10 homers all season. Both starts still ended up being great ones for Gray. His two starts at Chase were his only two times this season reaching double-digit strikeout numbers.

He’s made five starts against Arizona overall, but it’s not fair to ding him for poor performances in any season but this one. The Diamondbacks have had completely different rosters in each year. Outside of his two starts in Phoenix this year, Gray faced Arizona one other time in Denver, allowing three runs over five innings in a Rockies’ 6-2 loss.

In Wednesday’s game, Gray should be worried about facing J.D. Martinez. Martinez is the only current Diamondbacks player with a homer versus Gray, hitting two shots in six at bats. Jake Lamb has the most experience against him; in 15 plate appearances, he has four hits including two doubles. But Gray has historically had no problem with Paul Goldschmidt, who doesn’t have a hit in 11 at bats with five strikeouts. It’s anyone’s guess whether these stats will hold in the Wild Card game, as it’s more anecdotal than telling, but the numbers are interesting.

How can Gray outpitch Greinke?

It’s fairly simple. Gray needs his slider and curveball to be working. Those two pitches have accounted for nearly 70 percent of his total strikeouts this season. In his two starts at Arizona, he got a combined 16 whiffs on his slider and four with his curveball. If he can use those in two-strike counts to finish out at bats, he can be successful.

Jon Gray faces one of baseball’s best offenses on the road in the most important start of his career. He is ready.

Devan Fink is a Featured Writer for Beyond The Box Score. You can follow him on Twitter @DevanFink.