Edward Cossette and others have raised objections to my characterization of the Nomar deal (see comments). Edward writes:

To me, your data only confirms the veracity to Theo's reasoning that defense was the reason for the trade.

As others have pointed out, Epstein didn't have the luxury of hoping that Nomar was just "rusty."

Indeed, isn't that the whole point of using stats to make decisions, i.e, to remove the "gut feeling" aspect of evaluating players?

It's great that the numbers show Nomar got better after the trade and may in fact have been "rusty." But it's even better to have a GM that saw a problem and did something about it.

Meanwhile, you have absolutely nothing but pure supposition to support your argument "that defense was an excuse to move a player the Red Sox no longer wanted."

That's kind of weird for a stats guy isn't it?

I'm willing to admit that Edward has a point. So I'm going to step back from my earlier statement and look at the numbers again.

There are two things I look at as a stat guy. One is the number, the second is the context. A month and a half is a short time frame for an evaluation. Anything can happen in 100 or so AB (look at Jeter's April hitting numbers). And anything can happen on 100 ground balls or so. Nomar came back rusty. You can see it in his June hitting numbers. But by July he had recovered his swing. Why wouldn't his fielding numbers come back also? He did show range improvement in July, but his numbers were still poor. What was the context for believing the small sample size of poor fielding numbers were valid?

And I will admit that I haven't looked at context either. One is the context of his injury. I don't know how well the injury healed. It was good enough that he could hit well, but not good enough that he could play everyday. Obviously, the Cubs thought the injury healed well enough that they were willing to take Nomar in trade. It's possible that the Red Sox thought that Nomar's poor range would not improve due to the tenderness of his foot. That proved to be incorrect.

The other is the long term context of Nomar's fielding. Were his poor fielding numbers the continuation of a trend? This one I can research. Yes, it was the continuation of a trend. In both 2002 and 2003, Nomar ranked near the bottom of the pack in PMR for shortstops on the field for 1000 balls in play. In 2002, he ranked 31 out of 36. In 2003, he ranked 28 of 38. Was his range costing the Red Sox outs? Yes.

Nomar's offense, however, was making up for his defense. He did earn 52 win shares over 2002-2003. So, with Nomar's offense fine, did Theo really believe that Nomar's defense was costing them that much? Remember, the difference between a really great defensive shortstop and a really bad defensive shortstop over a full full season is 2 or 3 wins. And while Cabrera was good, he wasn't great. So you're talking about maybe 1 win defensively with Cabrera playing instead of Garciaparra. That doesn't seem to me to justify a trade on defense, especially when it's not a long term solution.

As it turns out, Nomar earned 1.7 defensive win shares with the Cubs, and Cabrera earned 1.7 with the Red Sox. Overall, Nomar had 6 win shares with the Cubs, Cabrera 5 with the Red Sox. The tangible evidence says the Red Sox would have done about the same with Nomar or Cabrera at short. The tangible evidence says defense wasn't that important. The tangible evidence says the Red Sox drew the wrong conclusion from 1 1/2 months of fielding data.

The intangible evidence says it was a great trade. Theo trades, runs allowed per game go down, runs scored per game go up and the Red Sox win the World Series. And every once in a while, Soriano swings at a low outside pitch and hits a home run. It's about process. Maybe this trade was about changing the personality of the team. That's fine, but I'd like to be told that rather than some fluff about defense. Maybe it was just that the Red Sox didn't want Nomar long term and tried to get what they could for him. There's nothing wrong with any of that, but they would have been rid of Garciaparra by the end of the year anyway.

Here's what I believe. Theo didn't go to ownership and say, "We have to trade Nomar because he's killing us defensively." I believe ownership came to Theo and said, "Get what you can for Nomar, and find a way to justify it." And yes, that's pure speculation. But I know Theo is a very smart guy and knows about sample sizes. I know he has a very good handle on the value of defense vs. offense. And knowing that, the explanation for the deal does not make sense to me.