Is Ian Kennedy the Diamondbacks' Ace of the Future?

With Diamondbacks starter Ian Kennedy leading the National League in wins, there’s been talk of him winning the NL Cy Young. Most of it is as a dark horse candidate, as Roy Halladay, Clayton Kershaw, and Cliff Lee (among others) have been better this year. However, it’s fairly clear that Kennedy has established himself as one of the NL’s better pitchers. Is he an ace going forward?

I would actually say not, but it doesn’t matter. The Diamondbacks have a much better potential ace going forward in Dan Hudson.


Kennedy has had a good 2011, without a doubt. As mentioned, he leads the NL, with an 18-4 record, and his 2.96 ERA and 167 strikeouts are very solid. However, he looks more like a (very good) number two pitcher going forward. His strikeouts and walks allowed are both solid, with a 3.27 ratio of Ks to walks. He’s allowed .88 home runs per nine innings, also solid. However, there are two areas that he has potential to slide back next year: he’s stranded 80.2% of base runners, and he’s allowed a .267 batting average on balls in play (BABIP). Both can fluctuate from year to year from things beyond the pitchers control (like luck, or the defense behind him). Granted, this may make his ERA rise from 2.96 to 3.30, for example. It won’t make him a horrible pitcher, but it will probably make him the second best pitcher on his own team.

I’ve seen several Arizona fans saying the team has an ace in Ian Kennedy and a solid number two starter in Dan Hudson; I think this view is actually backwards. Dan Hudson looks to be the more promising ace going forward. While his 15-9 record and 3.53 ERA looks less impressive than Kennedy’s numbers, his peripherals are slightly stronger. He has fewer strikeouts, but also walks fewer, meaning he has a better strikeout to walk ratio than Kennedy (3.63). He also allows fewer home runs, with .70 per nine innings. His luck has been rather the opposite of Kennedy’s, with a rather average .303 BABIP and a 70.3% strand rate that is towards the bottom of the league. The strand rate, at least, should lower through chance, which will lower his ERA.

There’s one more reason I think Hudson will be better, and it’s probably the biggest reason. Kennedy is in his age 26 season, while Hudson is two full years younger. This means that Hudson has much more potential for growth, as most players peak in their age 27 season. There’s a case that Hudson is already the better of the two, and he also is the more likely of the two to improve. In short, Kennedy is an All-Star pitcher right now, but Hudson is an All-Star caliber pitcher right now who may continue to improve.

So, Diamondback fans who say they have an ace and a number two starter for the next few years are probably right; they just might have confused which is which.