Why Were The Diamondbacks Better in 2011?

Just after the All-Star break, I took at look at what had spurred the Diamondbacks' impressive turnaround, asking Why Are The Diamondbacks Better In 2011? I extrapolated WAR numbers forward for the rest of the year, and found a projected improvement of 20.1 WAR. Looking at where that came from, the biggest factor was simply the non-presence on the 2012 roster of dead weight like Chad Qualls, Tony Abreu, Rodrigo Lopez, etc. Player improvement, year on year, was also significant, with Ryan Roberts the poster child there. What hadn't made much of a dent were the new arrivals: for every David Hernandez and J.J. Putz, there was an Armando Galarraga or Melvin Mora.

However, those numbers were provisional, and contained some obvious flaws. There was no way to predict the season-ending injury to Stephen Drew, and the extrapolation didn't take into account that Galarraga would not be troubling us the rest of the way. Now, with the numbers all in and the season in the books, let's revisit the final tallies of the 2011 season, and see whether those conclusions still hold true.

As with all the numbers in this article, I used Baseball-Reference.com's WAR, and have stuck to pitching WAR for pitchers i.e. excluded their hitting. Oddly, some of the 2010 numbers seems to have changed since the original piece: I've got no particular reason for this. The table below has four columns. WAR in 2010; WAR in 2011; the change between the seasons; and the final column lists what I had predicted their 2011 WAR to be in July. If this number is lower than the actual 2011 figure, it'll indicate the player concerned stepped up their game in the second-half - or, as we'll see often, means they weren't about to hamper the team's chances.

The final tally ended up a little lower than projected. The absence of Stephen Drew was obviously a factor, but Daniel Hudson and Gerardo Parra couldn't quite sustain their production in the second half. That countered the departure of Juan Gutierrez, Aaron Heilman, etc. from the full-year roster. The table also lets us see who were the most-improved Diamondbacks (by WAR) in 2011. The leaders there were Roberts (+3.7), Montero (+3.4) and Saunders (+2.6), which seem to pass the eyeball test reasonably well. In total, the "internal change" was worth 6.4 wins, which seems reasonable given the general youth of our roster.

2. Players who joined Arizona for 2011

This table lists the players who arrived in Arizona for the season, and there's just two columns: actual 2011 WAR and the mid-season projection. In total, the drop in internal production during the second half was largely countered by an uptick here, which resulted in 3.2 extra wins compared to July expectations. Two moves were key: the arrival of Hill (+1.7 WAR) and the exile of Armando Galarraga, whose absence "saved" the Diamondbacks about 1.2 WAR. The rest of the second-half moves, such as the signing of Marquis, did little or less than nothing. Despite the impact on morale of Goldzilla, his production didn't moved the needle very much.

Again, by comparing the 2011 and p2011 columns, we can see who surged in the second-half. A trio of players stand out there: J.J. Putz (second-half ERA: 0.77), Henry Blanco (second-half OPS: 1.031) and Bryan Shaw (2.25 second-half ERA, plus only threw 4.1 innings before the break). The total contributed by those not on the roster in 2010, ended up at 6.3 WAR, almost exactly the same amount as those who were present in both seasons, and double the mid-season number. So, by this measure, Towers' off-season acquisitions and in-season promotions did contribute a significant slice to our success by year's end.

3. Players who left Arizona after 2010

This aspect hasn't changed, of course - except for the odd adjustments in 2010 WAR noted above - and still remains the biggest factor in the team's improvement, adding up to more than eight wins added, simply by not having these players on the roster. Not all of them were worse than replacement, e.g. Brandon Allen and Chris Snyder, but those contributions were hugely outweighed by the gurgling vortext of suck represented by the likes of Chad Qualls, Tony Abreu and Rodrigo Lopez.

There's another stat which brings this number home. We can compare the number of innings thrown, by players who were at or below replacement level, between the two seasons

That's an astonishing amount of "garbage innings" thrown last year - 57% of all innings pitched by Arizona last year, were by someone whose performance was at or below replacement level. That number was slashed dramatically in 2011, and illustrates an interesting point: a team can improve significantly by raising the bottom of its pitching barrel. If we look at the bottom 816.1 innings by WAR pitched for us this year, that more or less covers everything not thrown by Ian Kenendy, Daniel Hudson and Josh Collmenter. Those 800-odd innings resulted in +3.5 WAR - thirteen wins more than the same innings gave us in 2010.

This perhaps sheds light on the D-backs pitching moves this winter, particularly with regard to the rotation. A win obtained by getting a less crappy #5 starter is worth exactly the same as one obtained by upgrading the top of the rotation - but the former costs a good deal less than the usual $4-5 million. If you're looking for market inefficiencies to exploit, it could be one such. At this point, Trevor Cahill has basically replaced the hodge-podge of #5 starters we used last year. They started 39 games, with a 5.56 ERA and about -2.0 WAR [that does include Duke and Owings relief-work]. Got to think Cahill should improve significantly on that, enough to offset regression from the others.

Summary
If you add up these three areas, you get about 21 wins more. Obviously, a hefty increase, it's short of the 29 win improvement seen by Arizona. However, it is closer to the 19 win improvement in Pyhagorean record: last year, the team wasn't as bad (going by runs scored + allowed) as their record suggests; this year's model overperformed a bit, mostly because of a stellar 28-16 record in one-run games. That's six games above random chance - there's little data to suggest winning one-run games is a repeatable skill, year on year, as the 2007-08 team found out - largely covering the difference between WAR improvement and W-L improvement.

This year, there will be less dead wood left to cull, though the absence of Heilman, Marquis and Galarraga is a good chunk of WAR we won't have to claw back in 2012.. All told, about -1.6 WAR isn't coming back in hitters, and probably about -3.7 WAR in pitchers, depending on what happens with the fringey arms. I think there's still room for some internal improvement:, most obviously from a full season of Goldzilla and a (hopefully) healthy Stephen Drew. On the other hand, will Miguel Montero and Ryan Roberts sustain their output, and I think overall, we'll remain fairly static. The final number may all come down to how new arrivals Jason Kubel and Cahill perform.