MLB.com Columnist

Mike Petriello

Rockies powered by unexpected pitching

Colorado has third-best xwOBA behind Dodgers, Astros

Rockies powered by unexpected pitching

The 2017 Rockies' pitching staff, by all rights, shouldn't be that good. That has nothing to do with Coors Field and everything to do with the fact that Jon Gray has been injured, Chad Bettis has been recovering from a fight with cancer, and that Tyler Anderson and Tyler Chatwood haven't lived up to their success from 2016. That's four-fifths of the expected rotation that has contributed little or nothing, and you could even consider it a full five when you add in that the club's No. 2 prospect, Jeff Hoffman, didn't win a spot out of camp and has spent most of the season in the Minors.

That should be enough to sink any team; it should really be enough to sink any team that calls Coors home. So why hasn't it crushed the Rockies? While their 4.31 team ERA doesn't look particularly impressive, their National League West-leading 22-13 record does, and a look at some of our new Statcast™ tools that attempt to really drill down to a player's skill shows something impressive is happening here -- and since these stats are headed into Wednesday's game, this doesn't even include German Marquez taking a no-hitter into the seventh inning against the Cubs.
 

McGee gets out of a tough jam

Let's start with something that's not nearly as complicated as it sounds, "Expected Weighted On-Base Average," or xwOBA. Don't run! This is simple, we promise. Every time a pitcher allows contact, you know how hard it was hit and at what angle. If you compare the outcomes of all similar batted balls across the game, you know how likely it was the pitcher just allowed a hit, independent of defense, and you can credit them for that. For example, last July 4, Gonzalez Germen got Angel Pagan to hit a poorly struck ball that turns into a hit just one percent of the time. He got nailed with a double because Charlie Blackmon lost it in the sun, but that has nothing to do with the pitcher. We credit him for the skill he showed in inducing a low-impact ball.

You do that for each batted ball over a season, you add in real-world strikeouts and walks, and suddenly what you have is a very good indicator of the pitcher's skill in missing bats and collecting unproductive contact. You can use that to compare his real-world batting average to his expected average if you like, but we prefer xwOBA, because it actually gives more credit for extra-base hits, rather than treating all of them the same. Think of it like OPS, if you like.

That explanation out of the way, we can rank the teams from 1-30 in expected wOBA, and you get a very good indicator of which pitching staffs are preventing dangerous contact and missing bats. Dodgers and Astros at the top, well, that makes sense; Clayton Kershaw and Dallas Keuchel are elite, and both have very good bullpens. Twins and Tigers at the bottom, that makes sense, too; Minnesota is rebuilding, and Detroit has the highest ERA in the American League. But would you believe Colorado and its depleted rotation is third?If you're wondering if this is a good indicator of success, last year, the Dodgers, Nationals and Cubs were the top three. The Reds, D-backs and Twins were the bottom three. That all checks out. You want to either be inducing poor contact -- which the Rockies do more often than only two other clubs -- or avoiding contact at all, and Colorado is doing that.

Remember, this has nothing to do with defense, so it's not about being bailed out by Nolan Arenado or DJ LeMahieu. If you prefer simply looking at who has taken steps forward since last year, the Rockies have made baseball's second-largest jump.

But how? Or, perhaps more appropriately, who? Chatwood, for example, is repeating last year's strikeout and walk numbers but seeing his home runs per nine jump from 0.85 to 1.85. Anderson, last year's exit velocity darling, has been better than he's looked, allowing a .391 wOBA when he has really only "deserved" an expected wOBA of .345, but .345 is still well above the Major League average of .316. (He did look outstanding in striking out 10 D-backs on Sunday, however.)

Let's lightning-round three reasons why:

1. Kyle Freeland has been legitimately fantastic.
Colorado's 2014 first-round pick -- and Denver native -- has been outstanding in his first seven starts, putting up a 2.93 ERA. He's earned it, too, because his actual wOBA allowed (.283) and his expected (.284) are essentially identical, and those are great numbers. Based on the quality of Freeland's contact, he's been one of baseball's 25 best starters this year, ahead of Gerrit Cole, Luis Severino and Carlos Martinez. Note that "has been" and "will be" are two different things, but we'll get to that.

Freeland gets Nunez to fly out

2. The bullpen has been outstanding.
There was reason to think the Rockies' relievers would have a good year, and they've lived up to it. Based on expected outcomes, they've had baseball's fourth-best bullpen, even if it's only the 12th-best ERA, which is affected by Coors. Greg Holland's return from a missed 2016 has been spectacular. Mike Dunn has thrown only nine innings, but they've been good ones. Adam Ottavino has had control issues, but he's still struck out 15 in 13 2/3 innings. Scott Oberg, Jake McGee and Chris Rusin have all put up expected wOBA marks better than average. Of semi-regular relievers, only Carlos Estevez and Jordan Lyles have been issues.

Holland secures the Rockies' win

3. They've been baseball's best run-prevention team on the road.
What we're showing is that Colorado has done a good job limiting dangerous contact, but because of where the club plays, that's not the same thing as limiting damage. Coors Field, as it does, leads to runs being scored. On the road, it's been a more interesting story, however. The Rockies have a 3.23 ERA, the best away mark in the game. They have a .304 xwOBA, the third-best mark in the game, and that backs that number up. What's interesting is that their home xwOBA is also .304, even though their home ERA is 5.28, the second highest. Coors Field is impossible -- even with a best-in-baseball ground-ball rate there.

Senzatela hurls six solid frames

So because things have been great, they will be great, right? And what of rookie sensation Antonio Senzatela, you ask?

Well, yes and no. Forty-one pitchers have thrown at least 40 innings this year, and Senzatela (13.6 percent) and Freeland (15.1 percent) have the lowest and third-lowest strikeout percentage, respectively. It's extremely difficult to see that kind of batted-ball contact success keeping up without an increase in whiff rate, especially as the league grows a scouting report on them. You can be almost certain they'll perform worse going forward than they have to date.

Gray, however, ought to be back soon, and he was a trendy breakout pick. Anderson's last start was among the best of his career. If we've learned anything about pitching in 2017, it's that the same five pitchers won't stick in the rotation all year long. For Colorado, besieged by rotation issues early on, the club has had some unexpected help from some unexpected places. It's the kind of thing you need to be in first place well into May.

Mike Petriello is an analyst for MLB.com and the host of the Statcast podcast. He has previously written for ESPN Insider and FanGraphs. This story was not subject to the approval of Major League Baseball or its clubs.