The Arizona Diamondbacks, owners of a 97-loss 2010 campaign that put them in last place in the National League West, currently hold a half-game lead in the division over the defending World Champion San Francisco Giants. Their record seems deserved, too, with a +21 run differential that is tops in the division. There are concerns about whether they can keep this up, though, as they have a potentially killer flaw: a lack of legitimate starting pitching.
The Diamondbacks aren't bereft of capable hurlers, of course. They have Daniel Hudson, in his first full season in the majors, following up on his brilliant debut with Arizona in 2010 (79-2/3 innings, 70 strikeouts, 16 walks, and a 1.69 Run Average in 11 starts) with another quality campaign (108 innings, 87 strikeouts, 25 walks, and a 3.92 RA in 16 starts). He isn't an ace, but he is a high-quality starter who makes the offense's job that much easier.
They also have Ian Kennedy, who, like Hudson, isn't going to be confused for Roy Halladay any time soon, but also is going to give Arizona a chance to win almost every time out. His numbers are very similar to Hudson's: in his 303 innings with the Diamondbacks the past two seasons, he has struck out 7.6 per nine, walked 2.9 per nine, and posted a 3.69 RA. Those are high-quality numbers (from both starters), especially when you consider that their home park is an offensive haven.
Things drop off precipitously after that pair, though. This organization -- well, the previous administration -- traded Max Scherzer and Dan Haren in the same season, and it shows in their starting pitching depth. Joe Saunders is listed as the #3 starter for Arizona -- the same Joe Saunders who has a 4.55 RA, strikes out a below-average number of hitters and has a higher HR/9 than K/BB ratio. His 5.09 FIP tells the story as well as any of those numbers -- this is not a guy the Diamondbacks can depend on for anything other than showing up to work.
He may legitimately be their third-best option, though. After Saunders comes Zach Duke, who, from age 23 through 27 with Pittsburgh, was the exact same person year after year. In that stretch, he struck out 4.6 batters per nine innings and posted a 1.9 K/BB ratio over the course of nearly 900 innings. While his ERA+ of 88 in that stretch had a lot to do with a consistently poor Pirates defense, it also had a lot to do with being Zach Duke.
He has just five starts and 29 innings pitched in 2011 thanks to a broken hand suffered during spring training. He has not done well in that stretch, either: despite walking less than a batter per nine innings (yes, you read that correctly), Duke has a 4.66 RA thanks to his sixth-straight season of being hit more often than a coach at batting practice. His career hits allowed per nine is 11.0, and he is at 13.0 this year (albeit in a small sample). DIPS theory tells us that BABIP is roughly the same for most pitchers, and that they have very little control over hits on balls in play, but if there are exceptions for allowing fewer hits (Clay Buchholz and Trevor Cahill come to mind), then there should also exceptions in the other direction, and Duke sure looks like one of them.
The wild card in the rotation is rookie Josh Collmenter. In his first eight starts, the right-hander has a 2.92 RA along with 5.4 K/9 and 1.9 BB/9. The strikeout rate is below-average, but his control has been exceptional. While his control was never that good in the minors, his strikeout rates were also never this poor -- in five seasons and 515 frames in the minors, Collmenter struck out 8.2 per nine and posted a 2.7 K/BB ratio.
When his free passes start to pile up more, the Diamondbacks will have to hope his strikeouts come back, too. The important thing is that he continues to keep a solid K/BB ratio, as giving up too many walks in a hitter's park like Arizona can be disastrous. He is the best bet on the current roster to be able to help them stay in this thing more than two out of every five days, but if he doesn't start to miss bats soon, that won't hold up.
Arizona may need to make a trade before the July 31 deadline to improve the rotation, as they don't have much help they can call on from the minors. Top prospect Jarrod Parker is in his first year back from Tommy John surgery, and is pitching decently enough at Double-A, but hasn't returned to form yet. Wade Miley is 24, but hasn't conquered Double-A yet, and looks like he would be about the same, if not worse, than the options they already have in place. Charles Brewer has pitched well at Double-A, but he looks like a back-of-the-rotation guy, and not a pitcher who will make a difference. Then again, anything that isn't Zach Duke might be considered a positive very soon. Patrick Corbin is yet another Double-A arm in the system, but he is just 21 -- he has, however, pitched very well at the level, striking out 8.1 per nine with a 3.9 K/BB ratio.
There isn't a whole lot to love on the trade market either, but adding someone like Brett Myers -- who is sure to be available this summer from the last-place Astros -- would be one way to plug a rotation hole, assuming the D'backs don't want to rush their kids. Myers would also give them another starter for 2012 (for $11 million, with an option for 2013 as well), so he would be more than a rental. That would cost more than, say, Jason Marquis or Jeremy Guthrie, but would also do much more for the club in a two month stretch.
Kevin Towers has a history of making trades that improve his team, so look for this to be the route he takes over the next month-plus. Something has to be done, though, as the club's current positive run differential won't hold up the more we see of Saunders and Duke, no matter how good the offense.