What's Going On With: The Arizona Diamondbacks

This is Part 3 of a six-part series looking at the three worst and three best teams in baseball to date, and figuring out why they've done what they've done and whether they'll keep on doing it. We're now up to the worst team in the majors, the Arizona Diamondbacks, with a worse record than the Chicago Cubs and Houston Astros.

How Bad Have They Been? The Diamondbacks are 8-21, a .276 winning percentage. Over a 162-game season, that's equivalent to going 45-117. They are a remarkable 2-14 at home.

How Much of a Surprise is This? The Cubs and Astros are teams that weren't supposed to be good and have simply been worse than expected. The Diamondbacks, though, seemed like an OK team going into the season. They were 81-81 in 2012 and 2013. Baseball Prospectus, FanGraphs, and ESPN projected 79-82 wins. This is easily the most disappointing team in baseball.

What's Been Wrong? The offense hasn't been great (tenth in the NL in runs per game, sub-.300 on base percentage), the defense has been weak (lowest percentage of balls in play turned into outs), but the problem's been pitching. The team's 5.27 ERA is a full run worse than every other team's in the league. The relievers haven't been bad, but the starters' ERA is a cover-your-eyes 6.32. Josh Collmenter (3.94 ERA in three starts) is the only starter with an ERA below 5. Losing last year's best pitcher, Patrick Corbin, to Tommy John surgery was a bummer, but come on.

Has Luck Been Involved? Please refer here for a discussion of the terms used below, and why I chose them.

There are a couple things that support the notion that the pitching will get better. Diamondbacks pitchers have allowed a .323 batting average on balls in play, highest in the league, a figure that is far enough above the league average of .292 that you'd think there's some bad luck involved, although the Arizona fielders' inability to get to balls may be an unfixable contributor. Only 8.3% of fly balls hit by Diamondbacks hitters have left the yard compared to 12.9% of fly balls allowed by their pitchers. Neither figure is too far removed from the league average of 10.6% but the difference is large enough to make it seem as if either the hitters will hit more homers or the pitchers will give up fewer.

What's The Outlook? We can sit here and agree that the team's starters should improve. Wade Miley (3.54 career ERA entering the season) shouldn't finish the year with a 5.36 ERA. nor  Brandon McCarthy (4.10) at 5.54 ERA (he pitched a strong game on Sunday), nor Trevor Cahill (3.89) at 7.66, nor Bronson Arroyo (4.19) at 7.77. But there isn't a lot of data suggesting that a sharp improvement is imminent. Just for reference, a 5.27 team ERA would be worst for a non-Coors Field National League team since the Astros' 5.42 in 2000.