Conor Jackson: Rapid Reaction

Maybe I’m missing something, but I don’t get the Conor Jackson trade. Granted, we’re not exactly giving up a ton in Jason Rice, a righthander originally out of the White Sox system. Rice has decent K rates – 9.39/9 and 89 in 85.1 IP this season in Pawtucket – but he walks too many (4.43/9) and 25 year old relievers who haven’t hit the majors yet aren’t in short supply.

That said, I’m not sure what the Sox see in Jackson. His career OPS numbers against LHP are better than McDonald’s – .825 to .789 – but Jackson’s having almost as tough a year as the bat he’ll presumably replace (or at least steal ABs from). His OPS against lefties this year is .686, while McDonald’s – his down year notwithstanding – is .768.

And then there’s defense. Fox’s Jon Morosi says the Red Sox envision Jackson playing a super utility role, bouncing between the outfield and infield. By reputation, Jackson’s not a stellar defender, having spent most of his career in left or at first base. The metrics bear this out, at least for this season. Though it’s foolish to place too much emphasis on single season defensive metrics, let alone partial season, McDonald grades out at 14.9 on UZR/150 this season, against Jackson’s 8.8.

As far as total value goes, WAR doesn’t love either player, though Jackson edges McDonald’s .3 with a .4.

We didn’t give up much, then, but it’s not clear that we got much in return. At his peak, Jackson was a useful 3 win player – a number McDonald won’t touch in his career. But that was three years ago and his decline hasn’t been gradual.

My guess is that the front office has identified something specific they like about the player – recent adjustments, a track record of success amongst possible playoff opponents (lifetime .714 OPS against the Yankees, .697 Texas, .932 Detroit) – something. It may be his versatility as Morosi claims, but I’m not quite sure I understand that; last I checked we’ve got three guys who can play first base, and five who can play the outfield (assuming Drew does come back). Or they know that Drew actually broke his finger and isn’t coming back.

And I’m sure that, as always, they weighed the cost and found it acceptable. Personally, I’m not for or against the transaction; I merely fail to understand it. Either way, it will be interesting to see how this plays out in terms of playing time.

Is There a Home Run Derby Curse?

With all the discussion of Adrian Gonzalez’ power outage – one homer in 102 ABs since the All Star Break – it’s no surprise that we’re seeing discussion of the Home Run Derby curse. What I haven’t seen thus far, however, is a look at whether there is statistical evidence to support the assertion that the Home Run Derby has a provably negative impact on participants’ home run rates following the contest. So I decided to check.

To save time in data gathering, I picked a single season, 2005. I picked 2005 only because it is the most frequently cited as evidence for the Home Run Derby curse; the winner, Bobby Abreu, had 16 homers at the break but hit only 6 after. The single season means, obviously, that I have a smaller sample size to work from, so the usual caveats apply. I also have made no effort to control for other variables such as games played, so bear that in mind as well.

What I’ve done here is look up the participants from MLB, then compare the players’ career pre/post All Star break splits with their numbers from the 2005 season (all splits taken from Baseball Reference). Here are those numbers:

As you can see, the differences in first and second half home run rates of 2005 compared to their career numbers is slight. For their career, participants have hit 56% of their home runs before the derby; in 2005 that number was 57%. Rather than take for granted that the one percent delta isn’t statistically significant, I ran a simple two-sample proportion test in R. In simple terms, this compares two proportions and determines whether a given proportion is equal for two different groups. The test, the results of which are included below, tells us that there is no reason to suspect that there’s a larger Home Run Derby curse at work; the difference in the observed percentages for the group is not statistically significant.

It’s possible that it affected Abreu – the result if you run the test on his numbers is just this side of significant (P-value of 0.05181), and we can’t prove that it’s not affecting A-Gon. But we don’t have any evidence to say that, in general, there is a curse.

Due to the aforementioned sample size limitations, this study shouldn’t be considered representative. But if someone tells you that Bobby Abreu is proof that there’s a curse on derby participants, you might want to point out that the effects of the “curse,” that year, were around 1% fewer home runs.

Appendix A: Test Results

2-sample test for equality of proportions with continuity correction

X-squared = 0.223, df = 1, p-value = 0.6367
alternative hypothesis: two.sided
95 percent confidence interval:
-0.08324864 0.04819810
sample estimates:
prop 1 prop 2
0.5561181 0.5736434

Appendix B: R Code for Two Sample Proportion Test

> rownames( colnames(
Before After
Career 1318 1052
2005 148 110
> prop.test(

Red Sox Trading Deadling Performance by WAR

Every year the non-waiver trading deadline generates fierce debate on the merits of a given trade. From talk show callers to prospect experts, everyone has an opinion on the winners and losers, the GM’s approach and the wider industry context on what’s being over or undervalued at that particular time.

Post-trade, however, most of the retrospective analysis is superficial and non-quantitative. Rarely do we see coverage of the longer term value differential of a particular trade, let alone the patterns of a particular GM over a period of time.

Curious then about what Theo Epstein’s return was against the trading costs, then, I ran the WAR numbers for the deadline trades made during his tenure. The list of traded parties was obtained from this excellent piece by Alex Speier.

The WAR calculations are derived from Fangraphs and counted the wins accumulated by players only for the teams involved in the transaction; Jason Bay, for example, is credited only for his WAR numbers with the Red Sox. His subsequent performance for the Mets is not considered. This analysis does not take into account the contract status of the players involved, importantly; Manny Ramirez’ entire tenure with the Dodgers, therefore, is considered.

It is also important to note that this is a snapshot; the longer term value of some of the traded assets – Nick Hagadone, for instance – is not yet determined and thus not part of these calculations. 2011 was omitted, in fact, because we have next to no data on the value contributed by either the pieces acquired or those traded.

With those caveats, here’s the data.

Red Sox Net Trading Deadline WAR

It may surprise some to learn that we have traded away approximately thirty wins (to date) in the last eight seasons. But it is actually the most probable outcome: even if we perfectly rate our prospects, we are – with rare exceptions such as last season – buyers at the deadline. Buyers, almost by definition, will be trading more value than they receive in return. The deadline represents the last time to acquire without restriction assets to improve your roster, and the marginal value of even fringe major leaguers can be magnified in tight races for a berth in the postseason. A half a win player could be, in fact, the difference.

This assertion is supported by the data. There is an obvious correlation between traded value and postseason performance; two of the top three years from a value traded perspective coincided with World Series wins. Half of the years where the net WAR total was non-negative, meanwhile, were years without a postseason appearance (2006, 2010).

The only thing that did surprise, ultimately, was the value of some of the players traded. His inability to get on base notwithstanding, Freddy Sanchez was, as Theo said, a pretty good player: he generated almost 12 wins for the Pirates during his time there. David Murphy, meanwhile, has been worth as much to Texas as Manny Ramirez was to the Dodgers, albeit in two more seasons. Erstwhile Red Sox reliever Joel Pineiro generated better than 6 wins for the Cardinals after leaving town, while Matt Murton was just shy of that number with the Cubs before heading for Japan. And so on.

Without comparing his performance to his peers – a task I don’t have time for at present, it’s difficult to quantitatively assess Epstein’s performance in context. And it’s true that it’s facile to point to the results – two World Series titles – because they may obscure fundamental flaws in the process.

But it’s worth observing that with rare exceptions like Justin Masterson (7.8 WAR and counting), the players Theo has resisted trading – but each of whom has been sought – are delivering much higher value than those that have departed.

All of which is a long winded way of saying that Epstein’s performance at the deadline seems more than adequate, the net 30 wins lost notwithstanding.

(Link to the source data I compiled in case anyone’s interested or wants to check it)