Evan Gattis trade: Putting a value on the Astros return and the prospects lost

First things first, if you don't like assigning values to players based on things like WAR, you will not like this story. If you do not like prospect valuation based on historical performance, you will not like this story.

But, if you agree that, based on production and the average cost of buying a win on the open market, you can assign a cost to players, then we can talk.

When the Astros traded for Evan Gattis from the Braves on Wednesday, many fans and writers reacted by saying the Astros gave up a ton of talent. One headline even said the deal was "pricey."

But, how much did it cost the Astros? We have the tools to figure out how much value they brought in and how much they sent away. Let's dive into the deal and figure out just how much surplus value got moved in this deal.

Wait, what the heck is surplus value?

Okay, maybe you didn't get scared off by my caveat at the top, but still aren't sure what the heck I'm talking about.

It's alright. I don't know what the heck I'm talking about most of the time, either. Just go with it.

Surplus value is an economic concept, but can easily be applied to baseball. Players have a value to teams that can be expressed in dollars. This is usually their salary. They also accumulate statistics based on their play in games. This is their production.

We can assign a value to that production, such as Wins Above Replacement. We can then assign a dollar amount to that WAR total, based on the cost of buying one Win Above Replacement on the open market. That price has been gradually rising for the past five or six years, but this winter has settled between $6 and $7 million.

After establishing a dollar figure for how much a player produced in a specific year, you can subtract that from his salary to get a surplus value to the team. Young players like Mike Trout who produce huge numbers have a ton of surplus value. Old players who are not productive and are on expensive deals, like B.J. Upton, have negative surplus value.

For a player like Evan Gattis, we can project out his value over the length of his team control, comparing it against projected future salaries. Thus, we get how much surplus value he's bringing the team in total.

Photo by Scott Cunningham/Getty Images

Prospect stuff

For prospects, valuation gets trickier. Victor Wang started this research a while ago. You can find the bulk of his findings here, complete with a summary of the value prospects bring to teams.

FanGraphs summarized some new research which updated the value of elite prospects. Since we can't know how they will perform in the majors, it's hard to know how much value they might have over that team control. So, we adjust for players in similar situations and see how much average WAR they produce.

Top 100 prospects generate much more WAR than guys down the list, which is why a guy like Mike Foltynewicz may be worth more in surplus value right now, even if Rio Ruiz may produce more value in the long term.

The Astros return

Houston gets Evan Gattis for the next four years. Gattis is still in his first three years of control, which means the team basically sets his contract. Last year, he made $520,250 and should make around that in 2015.

He'll go into arbitration next winter and will be there for three years. As part of this trade value calculator, we can estimate his future salary as 40 percent of his total production in Arb. Year 1, 60 percent in Year 2 and 80 percent in Year 3.

A conservative estimate of his WAR totals for the next four years is 2 fWAR per season. If he gets to that level, Gattis would be worth $35.4 million in surplus value to the Astros.

Houston's second piece, reliever James Hoyt, is a little harder to project. Wang's initial research suggested that pitchers who are C-level prospects and 23 or older are worth about $1.5 million in value. That figure may have gone up with the rising costs in baseball, but the chances that a C-level guy who's 28 provides a ton of value is small. Let's leave his value, then, at $1.5 million.

That leaves Houston with $36.9 million of surplus value gained in this deal.

Photo credit: Bob Levey/Getty Images

The new Braves babies

The Astros sent out a trio of prospects in right-hander MIke Foltynewicz, third baseman Rio Ruiz and right-hander Andrew Thurman.

Though Folty appeared in the majors last season, let's go off his prospect status and assume he keeps his Top 50 pitcher status. That makes him worth $18.7 million in surplus value, according to the new research done.

Rio Ruiz was rated as a B prospect last season and had a good year at Lancaster. Let's assume he keeps that while not moving into the Top 100 list. That means he'd be worth $5.5 million via Victor Wang's research. Let's adjust up, slightly, for any changes in WAR value and say he's worth $7.5 million.

Andrew Thurman is also a B prospect, worth $7.3 million by Wang. Let's adjust that more conservatively and go up to $8 million.

That means Houston gave up $34.2 million in value to the Braves.

The price of the deal

Add all of that up.

The Astros sent out $34.2 million in surplus value.

They got back $36.9 million in surplus value.

That leaves them with a slight edge in the deal, but overall, things look pretty even. And, that's how it should be. Trades rarely are as unbalanced, value-wise, as they seem. When one of the teams involved is the Astros, who have many smart people able to do projections and valuations much more complicated than I can, you can bet that number will usually be just about even.

Was this trade pricey for the Astros? It was, but they got a pretty fair return on what they gave up. Trades have to hurt both sides and it seems this one did a good job of walking that line.