Re-Evaluating Nova vs. Hellickson
Last week I took a brief look at some of the American League rookies from this past season and subsequently submitted my ballot for who should receive the Rookie of the Year Award. After reviewing their statistics on the season and after some internal deliberation I ultimately chose Kansas City’s Eric Hosmer as the most deserving candidate, with Los Angeles’s Mark Trumbo and New York’s Ivan Nova rounding out my Top 3 choices. Absent from that trio was Tampa Bay’s Jeremy Hellickson, the favorite amongst much of the more mainstream media who have posted their selections over the past few days.
My omission of Hellickson also caught the ire of one of my loyal readers who comments under the name “mlblogsyossif”. He’s a big Rays fan, writing for the blog Rays Rant (here is his look at the AL ROY race from early September) in addition to reading my thoughts on a regular basis. In short, he was shocked, outraged, and confused as to why Hellickson was omitted from my ballot. So, considering his passion on the matter, I thought maybe it would be worthwhile for me to take a second look at what the young right-hander did this past season.
|Player A||Player B|
|28 (27)||G (GS)||29 (29)|
For the sake of argument, we’re going to compare Hellickson’s stat line to that of Nova, who did make it onto my ballot. For the moment, at least, I’m going to refrain from identifying which player above is which.
Those who are more in the “traditional camp” when it comes to statistics will go right for the two players’ records and make their decision. Player A won 16 games, a great total for an All Star caliber starting pitcher, let alone a rookie. While Player B’s 13 win total is impressive, it’s diminished a little when placed next to 10 losses. 13-10 (.565 winning percentage) just looks more mediocre than 16-4 (.800 W%). But therein lies one of the fundamental problems with basing everything on a player’s Win-Loss record.
So we need to expand our thoughts a bit. We’ll start by adding in the other two pitching Triple Crown numbers – ERA and strikeouts. From a pure numbers standpoint, Player B comes out on top in both categories. Player B finished the 2011 season with a 2.95 ERA and 117 total strikeouts. Player A finished with a 3.70 ERA and 98 Ks. Based on the three Triple Crown categories, Player B comes out on top in 2 of the 3.
However, as statistics have continued to evolve over the past few years there are new factors which we use to evaluate performance that need to at least be considered here. These rate statistics are effective because they can frequently level a playing field when you factor in varying workloads from one player to another. In this situation, Player B pitched 33.2 innings more than Player A. As such, Player B had more opportunities to add to his total numbers but looking at things through the rate statistics gives us a more accurate look at how their performances compare side-by-side.
Now, the numbers are remarkably similar for the two players – which I had not expected when I decided to complete this exercise. The differences in both BB/9 and K/9 (for me at least, two of the more important rate stats to take into account) are minimal while there isn’t a single outlier that swings the discussion strongly in favor of one player over the other. So we’re at a bit of a standstill.
We could use WAR (wins above replacement) as our determining factor but there is a problem with that idea as well. The two widely accepted calculations of WAR each use a different method (centered on which defensive metrics to use), thus providing very different results. Baseball Reference lists a 4.2 to 3.5 win for Player B. Yet, FanGraphs shows a 2.7 to 1.4 win for Player A. Generally speaking I tend to gravitate more towards the Baseball Reference version, but the margin of difference here isn’t enough to make a decision based purely on the numbers.
Ultimately at the end of this exercise we need to go with our gut as to who the better rookie was this past season. And that gut decision will vary depending on numerous factors – whether you value wins more than ERA, what stats you weigh more heavily, even what team you root for. For me, I still feel that Player A, Ivan Nova, outpitched Player B, Jeremy Hellickson, during their rookie seasons.