The Oakland A’s made a huge trade yesterday, sending their biggest name, Yoenis Cespedes, and a draft pick to the Boston Red Sox for Jon Lester and Jonny Gomes. They also made a smaller trade, sending Tommy Milone to the Minnesota Twins in exchange for Sam Fuld. Of course, the sports world was abuzz from the Cespedes trade, which stunned many.

A couple of things left me unsatisfied about the reactions I’ve seen of the Cespedes trade. One is an old idea, expressed in Moneyball back in 2002: you don’t try to replace Giambi/Cespedes with one player, you replace him with other players in aggregate across the roster. The other a newer idea: is that the A’s platoon so much, that you can’t just analyze A’s players as atomic units. You can’t just say X is a 5 WAR player and Y is a 2 WAR player, and X – Y = 3 WAR. You have to break them down into their platoon split components, because the A’s use platoons far more efficiently than is baked into most of these formulas.

For example, if you look at Jonny Gomes as an atomic unit, he has suffered a severe decline this year. He’s hitting .234/.329/.354 this year, a far cry from the .262/.377/.491 he hit with the A’s in 2012, and in no way close to being able to replace Cespedes’ production. However, if you break Gomes down into platoon splits, you can see that his decline is entirely against right-handed pitching, where he is hitting a godawful .151/.236/.258 this year. Against left-handed pitching, however, he is still hitting a very healthy .302/.400/.431. A’s manager Bob Melvin is a master at getting the platoon advantage for his players, so we can bet we won’t see much of Jonny Gomes against RHPs.

So what I want to see is an analysis that really looks at the A’s as two teams: one team against RHPs which plays 72% of the time, and another team against LHPs which plays 28% of the time. Let’s look at those teams before and after the trade, and see how much the trades affected those two teams, even if we calculate these things in a kind of quick and dirty fashion.

To do that, you need to project performance by splits, which isn’t easy to find. PECOTA has a Marcel-like calculation called “Platoon multi”. Dan Szymborski pointed me to a platoon projection spreadsheet he created for his ZiPS projection. So I took that pre-season projected data, and combined it with their 2014 performance in a spreadsheet, to create a rest-of-season projection. (Okay, that wasn’t so quick, so the rest of this will be kind of dirty. We don’t have to be precise here, we just want a ballpark understanding of what’s going on.)

There’s another complicating factor here, in that the A’s currently have three players who are injured: Coco Crisp, Craig Gentry, and Kyle Blanks. Plus, Stephen Vogt has an injury that prevents him from catching, but not playing 1B or OF. So we’re going to run one set of numbers assuming everyone is healthy, and another assuming these injuries. Here are the best-hitting lineups (not by batting order, but sorted by GPA, from best player to worst). We’ll make removed (traded or optioned) players red, and added players blue.

Healthy lineup vs LHP: (position,obp,slg)

Donaldson (3b, .373, .604)
Norris (c, .399, .519)
Gomes (dh, .380, .440)
Cespedes (lf, .332, .473)
Crisp (cf, .353, .411)
Moss (rf/dh, .326, .439)
Blanks (1b, .336, .407)
Gentry (lf/rf, .348, .361)
Lowrie (ss, .320, .395)
Callaspo (2b, .304, .324)

Bench: Fuld, Vogt, Burns, Reddick, Punto, Jaso, Sogard.

Estimated runs per game, new lineup: 5.266
Estimated runs per game, old lineup: 5.218

The offense improves vs LHPs, because Gomes is actually slightly more productive than Cespedes, thanks to his high OBP. The defensive effect is that Moss gets moved from DH into the outfield, because he’s a better fielder than Jonny Gomes, but not a better fielder than Cespedes.

Healthy lineup vs RHP:

Jaso (dh, .372, .452)
Moss (lf/1b, .333, .510)
Reddick (rf, .325, .458)
Vogt (1b/c, .328, .422)
Cespedes (lf, .302, .453)
Crisp (cf, .321, .417)
Lowrie (ss, .329, .395)
Donaldson (3b, .321, .404)
Callaspo (2b, .333, .351)
Norris (c, .331, .353)

Bench: Blanks, Gentry, Fuld, Sogard, Punto, Gomes, Burns.

Estimated runs per game, new lineup: 4.810
Estimated runs per game, old lineup: 4.841

Losing Cespedes against RHPs has a more noticeable effect. Gomes and Cespedes are equivalent players vs LHPs, but the gap between Cespedes and his replacement against RHPs, Derek Norris, is larger, and creates a slight loss of runs per game. It also shifts Vogt and Moss around defensively to get Norris into the lineup.

Injured lineup vs LHP: (position,obp,slg)

Donaldson (3b, .373, .604)
Norris (c, .399, .519)
Gomes (dh, .380, .440)
Cespedes (lf, .332, .473)
Moss (lf/dh, .326, .439)
Fuld (cf, .337, .378)
Lowrie (ss, .320, .395)
Vogt (1b, .275, .448)
Callaspo (2b, .304, .324)
Burns (cf, .318, .292)
Reddick (rf, .245, .411)

Bench: Punto, Jaso, Sogard.
Out: Crisp, Blanks, Gentry.

Estimated runs per game, new lineup: 5.023
Estimated runs per game, old lineup: 4.852

Yeesh, those are some atrocious OBPs at the bottom of the lineup with these injuries, because LH batters Vogt and Reddick are forced into the lineup against LHPs. Fuld is also a LH batter, but he has a weird reverse platoon split in his career; he’s actually been better vs LHPs than RHPs. Like with the healthy group, going from Cespedes to Gomes is a slight upgrade against LHPs; but the upgrade from Burns to Fuld is enormous.

Injured lineup vs RHP:

Jaso (dh, .372, .452)
Moss (lf/rf, .333, .510)
Reddick (rf/cf, .325, .458)
Vogt (1b, .328, .422)
Cespedes (lf, .302, .453)
Lowrie (ss, .329, .395)
Donaldson (3b, .321, .404)
Callaspo (2b, .333, .351)
Norris (c, .331, .353)
Fuld (cf, .311, .321)

Bench: Sogard, Punto, Gomes, Burns.
Out: Crisp, Blanks, Gentry.

Estimated runs per game, new lineup: 4.685
Estimated runs per game, old lineup: 4.708

The main effect here is that Fuld gets Cespedes’ at bats, and that Reddick can move back to right field. But without the Fuld trade to complement the Cespedes trade, Sogard would be getting Cespedes’ at bats, and you’d have an awful outfield of Moss-Reddick-Vogt with Callaspo at 1b. Yeesh. You’re going to lose some offense, but that defensive alignment would probably kill you. I suspect that avoiding that defensive alignment alone is probably justification for trading Milone.

So let’s take those estimated runs per game, and extrapolate them over 162 games, and assume the average split of 72% RHPs and 28% LHPs, and combine those two split-handed teams into one team again, leaving us with just a healthy team and an injured team.

Of course, the injured team is not as good as the healthy team, and will be scoring fewer runs than the healthy team. But to analyze the trades, we don’t need to know the raw totals, we really only need to know how much the trades change the run scoring.

The healthy team loses 3.6 runs vs RHPs in the trades, but gains 2.2 runs vs LHPs, for a total loss of 1.4 runs over a whole season. It’s practically no loss of offense at all.

The injured team loses 2.7 runs vs RHPs in the trades, but gains 7.8 runs vs LHPs, for a total gain of 5.1 runs over a whole season. Most of that gain is from playing Fuld over Burns (vs RHPs) and Reddick/Vogt (vs LHPs).

Let’s say these three injured players are going to miss one-third of the remaining games to play. Multiply that 5.1 by one-third, and the -1.4 by two-thirds, and what you end up with is actually a slight gain (0.25 runs over the rest of the season), albeit so small that it is practically a wash.

The trades felt like a shock to many of us. On the surface, losing Cespedes’s sexy bat hurts, and trading a decent starting pitcher like Tommy Milone for a fourth outfielder seems like a waste. In a vacuum, that is true. But if you look at the impact those trades have on this particular team’s offense, it’s negligable.

Offensively, the numbers tell us that losing Cespedes is no big deal. And if everyone is healthy, trading for Fuld is a waste, because he wouldn’t play. But not everyone is healthy, especially in CF, and so Fuld is essential to keeping the offense at the level it would be without the trades.

So basically, we can consider the offense a wash. Now we can move on to analyzing the effect these trades have on the A’s defense and pitching. But I’m leaving that as an exercise for the reader. I’ve done enough for today.