The Arizona Diamondbacks were supposed to drift quietly through the 2011 season, as new GM Kevin Towers sorted through the roster in his first full season on the job, figuring out how to build the same kind of winner in the desert as he did by the sea in San Diego. For about six weeks, the D-backs played to form, starting 15-22 and drifting to the bottom of the NL West.
It's rare that managers have a dramatic impact on a team's season, but in the case of this year's D-backs, Kirk Gibson made a couple of choices that were critical in turning things around. The back of the rotation, Barry Enright and Armando Galarraga, had simply been terrible: 14 starts, 61 runs allowed in 77 1/3 innings. The Diamondbacks went 5-9 in the games that those two started. On May 4, Enright made the last of his six starts, and on May 16, Galarraga made the last of his eight. In their stead, Gibson placed rookie right-hander Josh Collmenter and returning lefty Zach Duke. (Micah Owings also made a couple of starts before Duke was ready to go.)
The change was dramatic. Collmenter, in particular, has been spectacular in the rotation, his funky over-the-top motion producing a 1.05 ERA in 34 1/3 innings over six starts. Combined, the three replacements have made 11 starts, thrown 63 2/3 innings with a 36/9 K/BB and a 1.84 ERA. The Diamondbacks, 5-9 from those two rotation spots before the changes, are 8-3 in them since. That's one of the biggest reasons for a 21-8 run that launched the D-backs into first place at the end of May, and currently has them in second, a game behind the Giants.
Stabilizing the back end of the rotation has made a big difference for a team whose front has been very effective. Ian Kennedy and Daniel Hudson have been pounding the strike zone and doing an excellent job of keeping the ball in the park -- 13 homers combined in 186 2/3 innings. For Hudson, there's some good fortune involved, as he has allowed an insane 3.7 percent HR/FB rate, third-lowest in MLB. Nevertheless, the combination of a solid front and the reworked back has made the Diamondbacks' rotation a strength for the first time since Brandon Webb was its anchor.
If the in-season changes to the rotation are a big factor, the offseason adjustments to the bullpen may be even bigger. The 2010 Diamondbacks had one of the worst bullpens ever, with a 5.74 ERA. Led by J.J. Putz's 2.00 ERA and 27/6 K/BB, D-backs relievers have posted an ERA more than two full runs better, 3.65. Nearly all of the good work has come from new arms, many added by Towers. Relievers who did not appear in the '10 bullpen (Putz, Collmenter, rookie Bryan Shaw, Rule 5 pick Joe Paterson, and the two right-handers that the Orioles sent back in the trade for Mark Reynolds, David Hernandez and Kam Mickolio) have a 2.76 ERA in 94 2/3 innings. One of the questions about Towers was whether his knack for building inexpensive, effective bullpens would make the trip inland -- and to a better hitter's park. Through two months, it has.
Woven into these improved pitching numbers is a defense that rates among the best in franchise history. The Diamondbacks are third in the NL in Defensive Efficiency (a stat that measures a team's ability to turn balls in play into outs). This is critical to a pitching staff that doesn't strike out a ton of guys (10th in the NL). Even noting that everyone's DER is up this season, the Diamondbacks haven't ranked in the top half of the league since 2001 -- and that team won not just the NL West, but the World Series.
It's not immediately apparent why the team has improved defensively however; the infield corners have changed, with Ryan Roberts and a mix of players replacing Reynolds at third base and Adam LaRoche at first. There's a case that the total impact is a defensive upgrade, though not a large one. Gerardo Parra taking an increased share of the leftfield innings may be helping, and the collective outfield range of Parra, Chris Young and Justin Upton seems to be one of the best in baseball. The D-backs have allowed an above-average number of doubles and triples, and a below-average number of singles, but that's about having the lowest groundball/flyball ratio in the league. This is something to watch: If the defense doesn't keep turning balls into outs, the run-prevention could get ugly in a hurry.
Even with all the changes, this hasn't been a particularly strong run-prevention team. The Diamondbacks have allowed 284 runs, 11th-most in the 16-team NL. They are still a team that relies on its offense to win ball games. After striking out 486,000 times over the past three seasons (rounded up), the Diamondbacks made a big deal about making more contact in 2011. They let LaRoche walk and traded Reynolds, dumping league-average offense and replacing it with...well, they didn't. They brought in a bunch of players worse than those two and hoped for the best. Ryan Roberts and Juan Miranda have panned out, with both journeymen putting up career-best numbers and taking over at third base and first base, respectively.
The Diamondbacks have cut their strikeout rate by about 20 percent, from one in every four PAs to one in five. In doing so, they have jumped from eighth in the league in runs to third. The remarkable thing isn't the reduced strikeouts, though -- it's the balance. Seven of the eight Diamondbacks regulars have been at least league-average hitters; the eighth, Kelly Johnson, is just below that line. No one is having a big year -- Justin Upton has the highest OPS, with a .272/.364/.492 line that ranks him 15th in the league -- but five players are having good ones and no one is hurting the team, which means the D-backs can create a rally from any spot in the lineup.
The Diamondbacks launched themselves into the conversation with a 13-1 stretch that pushed them into first place on Memorial Day. Since that hot streak ended, they've been grinding, going 6-6 in their last 12 games. After wrapping up a road series with the Marlins on Monday night, the Diamondbacks come home to play a big three-game set this week in Phoenix against the Giants before catching a soft spot in the schedule: interleague play against most of the AL Central and the A's. Because of that schedule, the Diamondbacks are likely to stay in contention in the weak NL West for some time. With so much of their success this year predicated on supporting players having their best seasons -- Miranda, Roberts, Parra, Hernandez -- and the bullpen already fading a bit (5.90 ERA in June, and Putz has been dealing with a back problem), the long-term outlook is less rosy. Gibson and Towers have already pulled a few rabbits out of their hats; they'll need to find more to keep the D-backs in this race all year long.