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Which NL West surprise will last?

The Diamondbacks and Rockies are right in the mix in the National League. Which club is more likely to sustain it?

MLB: Arizona Diamondbacks at Colorado Rockies Chris Humphreys-USA TODAY Sports

We’ve officially eclipsed the quarter mark in the 2017 Major League Baseball season, and two NL West teams have jumped out to surprising starts.

The Rockies and the Diamondbacks are in first- and second-place, respectively, in the division. Colorado, in fact, has the second-best record in the sport at 30-17. This is coming on the heels of a 2016 season in which those two teams finished in third and fourth in the NL West, both over 15 games behind the division-winning Dodgers.

One look at the FanGraphs’ playoff projections says it all.

NL West Playoff Odds
Chart via FanGraphs

The two teams started the season off with approximately a 10 percent chance to make the postseason, and the odds have steadily increased to around 55 percent today. Still, FanGraphs acknowledges the possibility of a collapse — there is three-quarters of the season left to play. With that said, however, these teams are obviously trending in the correct direction. Now, who actually has the better chance to make the postseason? Obviously, FanGraphs says the Rockies. But with just a 5.5 percentage point disparity, this really could go either way. So, let’s take a look at the two NL West surprises side by side.


The Diamondbacks and the Rockies are two of the highest scoring teams in baseball. Arizona has averaged 5.02 runs per game, ranking 8th, while Colorado has averaged 5.13 runs per game, ranking 4th. Both these offenses seem to be high-scoring juggernauts, but when looking at it a bit deeper, it becomes clearer as to which team leads this category.

Offense, Diamondbacks vs. Rockies

Diamondbacks 8.6 0.790 0.338 101 8.6% 22.9% 66 46
Rockies 3.9 0.767 0.329 82 7.1% 22.8% 62 12

The Diamondbacks are leading in nearly every category across the board, and their offensive output is exemplified when using park-adjusted stats such as wRC+. Chase Field (the Diamondbacks’ home) is a hitter-friendly environment, but it does not compare to the offensive heaven that exists at Coors Field (the Rockies’ home). That’s why their team wRC+ is 20 points higher.

Both the Diamondbacks and Rockies have a star player that carries the load in the form of Paul Goldschmidt and Nolan Arenado, respectively. But, the depth of the Diamondbacks’ hitters is significantly better than that of the Rockies’. Minimum 100 plate appearances, seven Diamondbacks have a wRC+ that is greater than 100, compared to the Rockies’ three.

The gap could close, however, if DJ LeMahieu (86 wRC+) and Ian Desmond (63 wRC+) get hot and begin to produce at 2016 levels. Carlos Gonzalez (59 wRC+) and Trevor Story (65 wRC+ and freshly off the DL) also remain as question marks. The fact that the Rockies are 30-17 with those four players hitting below the league average is commendable, though.

On the flip side, players such as Chris Owings (116 wRC+) and Brandon Drury (107 wRC+) are playing well beyond their career averages out in the desert, helping to boost a Diamondbacks’ lineup that was not supposed to be nearly as potent as it is. Despite that, though, A.J. Pollock is hurt, and his return could make this a sustainable weapon.

Advantage: Diamondbacks


Only two teams have allowed fewer runs per game than the Diamondbacks at 3.91. The Rockies find themselves more in the middle of the pack, allowing 4.49 runs per game, ranking 14th in the Majors. Once again, this isn’t the full story, but it does give us a good look into past performance. Let’s take this a bit deeper.

Pitching, Diamondbacks vs. Rockies

Team Starters ERA Relievers ERA Total ERA FIP xFIP FIP- xFIP- WAR
Team Starters ERA Relievers ERA Total ERA FIP xFIP FIP- xFIP- WAR
Diamondbacks 3.59 3.72 3.63 3.74 3.75 88 89 6.4
Rockies 4.33 4.10 4.24 4.03 3.99 88 94 6.6

When looking at it in a broader context, the Rockies are a bit better than the Diamondbacks at this facet of the game, but it is certainly a whole lot closer.

Let me direct your attention to FIP-. This statistic looks at a player’s (or team’s) FIP and adjusts it using park- and league-factors. Basically, it’s park-neutral, and it allows players that play in completely different environments to be compared. That’s why, when looking at the Rockies, it’s especially important to use park-adjusted data. While the team’s ERA may seem high at 4.37, that is actually a pretty good number when looking at the bandbox that is Coors Field.

That makes this debate a whole lot more interesting. The Diamondbacks do a better job at preventing runs than the Rockies, but a lot of the runs Rockies’ pitchers give up are just a Coors Field side effect. That’s why Colorado actually ranks fifth in baseball in pitching fWAR; their pitchers are doing a significantly better job than a replacement level pitcher would when given the same environment.

Led with a rotation that consists of five guys that I may have only heard of once or twice before this year — Kyle Freeland, Antonio Senzatela, Tyler Anderson, Tyler Chatwood and German Marquez — and a relief staff that’s been led by a resurrected Greg Holland, the Rockies are dominating the pitching.

But that doesn’t mean that the Diamondbacks’ pitching deserves to go unnoticed. Zack Greinke is having a bounce back year, and my personal favorite Archie Bradley is dominating out of the bullpen. What about Shelby Miller, for whom they traded former No. 1 overall pick Dansby Swanson? He’s out for the year with Tommy John surgery, continuing to solidify that trade as one of the worst in recent memory.

Dave Stewart’s front office is gone, though, so it’s really time to stop ripping them for this move.

Advantage: Wash, with the potential to lean Rockies

Defense and Miscellaneous

Defensive statistics are still not the best at determining which player or team is truly better than another, but if you can find agreement between them, it is possible that you are on to something. In this case, when comparing the Rockies and the Diamondbacks, we may be on to something.

Defensive runs saved (DRS), ultimate zone rating (UZR) and FanGraphs’ defensive rating all agree that the Rockies are significantly better than the Diamondbacks defensively. The question becomes, then: how much better?

Defense, Diamondbacks vs. Rockies

Team DRS UZR Def
Team DRS UZR Def
Diamondbacks -1 -2.1 -3.1
Rockies 8 9.8 10.8

All three rating systems see the Rockies’ defense as between 9 and 14 runs better than the Diamondbacks’. Most sabermetricians believe that around 10 defensive runs equates to one added win, so the Rockies have already, in theory, have added about one more win to their record than the Diamondbacks have just from defensive efforts.

Defense aside, though, it’s important to look at the two teams’ run differential thus far. The Diamondbacks are a +52, while the Rockies are just a +30. Using their pythagorean records, the Rockies are the luckiest team in baseball, with four more wins than their run differential would suggest. This is due in large part to a 9-0 record in one-run games, something that is definitely unsustainable. As for the Diamondbacks, they have one less win than expected, speaking to the strength of their team. Run differential and pythagorean record are two of the most suggestive statistics when determining whether a team’s success is sustainable, and the Diamondbacks seem to be much better prepared to face adversity than the Rockies.

Lastly, I want to take one quick look at the team’s managers, both who are in their first seasons with the club. The Diamondbacks have first-year manager Torey Lovullo, who served on the Red Sox’s staff during their World Series winning team in 2013. But, the Rockies employ Bud Black, one of the most well-respected managers in the game, despite never qualifying for the playoffs. I’ll give the slight advantage here to the Rockies, though Black’s lack of postseason experience could certainly haunt them down the stretch.

Overall advantage: Diamondbacks

A last look

Both the Diamondbacks and the Rockies are dominating the National League right now, but only one team appear to be set for a true postseason run down the stretch, and that is Arizona. The Rockies have too many offensive concerns and a run differential that is, at the moment, too low to suggest that they’re ready to make a run. The Diamondbacks are not only playing well beyond their projections, but they are backing it up with the runs scored and the runs allowed.

It’s been a fun start for both these teams, but despite what FanGraphs says, the Diamondbacks could very well be the team that sneaks into the National League playoff picture come October.

. . .

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