Who got the most out of the Shelby Miller trade?
At the moment, based on present values of prospects, players and wins? It’s the Braves. Based on the industry consensus? It’s the Braves. Based on which team will be better next season? Maybe still the Braves. How did Arizona get so comprehensively fleeced in this deal? There have been some great articles written on FanGraphs these past two weeks about the GM of the Arizona Diamondbacks. Dave Stewart seems to want to do things differently from all other teams, going with his gut when building a roster. Gut decisions can work. His gut identified Shelby Miller as a good player and so wanted him on his team. But wow did this gut decision miss something. How much something? How about 225 million dollars?
That’s right, I am suggesting that, with present values of prospects, players and wins, Dave Stewart, GM, gave away $225M more value in this trade than he got back. See below for how I got to that number.
FanGraphs’ staff have been using a great contract tool recently to estimate the value of major-league free agents. It estimates that players get better each year until aged 27 then worse each year after reaching 31. I’ll be following their method, which estimates an aging curve using WAR where players improve by 0.25 WAR each year in their 18-27 age years, keep steady WAR in their 28-30 age years and get worse by 0.5 WAR each year in their 31-37 age years. It also includes an inflation increase in the market value for each WAR, starting at $8.0M in 2016 and increasing by 5% each year going forwards. We end up with an estimated value for players over the lifespan of their contract.
I’m going to use last season’s FanGraphs WAR as the starting value for any major-league players (I’ll discuss the minor-league prospects later). I realise I could use ZiPS or many other predictors of players performance (which offer much lower WAR values), but it seems fair as both major-league players in the deal have some issues with their peripheral numbers that seem to balance out. The tool is an estimator based on current performance, so it seems fair we start with what they achieved this last year. Anyway, let’s get started.
The Major Leaguers
Shelby Miller (worth $98.48 M) – to Arizona
|2016||25||3.65||$8.0 M||$29.20 M|
|2017||26||3.90||$8.4 M||$32.76 M|
|2018||27||4.15||$8.8 M||$36.52 M|
Ender Inciarte (worth $172.91 M) – to Atlanta
|2016||25||3.55||$8.0 M||$28.40 M|
|2017||26||3.80||$8.4 M||$31.92 M|
|2018||27||4.05||$8.8 M||$35.64 M|
|2019||28||4.05||$9.3 M||$37.67 M|
|2020||29||4.05||$9.7 M||$39.29 M|
Holy cow! Not looking good for Arizona already. Shocked how much Inciarte is worth by this model? Me too. Those wins get expensive. He’ll do well to keep his performance at this level, but I’d argue that Miller has the same issue.
The Minor Leaguers
This isn’t quite as simple to work out. Minor-league players have a habit of not making it to the majors (an average 70% bust rate of ranked players not making a significant contribution to the major league team, according to this excellent article by Scott McKinney). I have used the valuations on ranked MLB prospects from Kevin Creagh and Steve DiMiceli with a couple of modifications.
Summarised, using historical prospect rankings, they took prospects ranked between 1-100 in the top prospect rankings each year and found the average WAR produced over their first six major league seasons at different rankings. These values are in the table below:
|Tier||Number of Players||Avg. WAR||Bust % Zero WAR or less|
Creagh and DiMiceli were looking at surplus value produced by a prospect. I’m more interested in total value. For each ranked prospect (Blair and Swanson) I found the average WAR produced by historical players with a similar prospect ranking (potentially flawed; I’d probably prefer median WAR for each group), then used an inflation model (again 5% per year starting at $8.0M/WAR in 2016) and an assumption that 2/3 of a prospect’s value is accrued during years 4-6 in the majors to find an estimate for total value.
Finally, some minor-league prospects don’t improve enough to reach the majors (they “bust”) so they aren’t as valuable as major-league players. This reduces the value of the prospect. Lower-ranked players are more likely to bust than higher ones so they should have a greater reduction in their value. The historical likelihoods of a prospect bust are shown in the table above (Bust % Zero WAR or less) for different ranks of prospect (again from Creagh and DiMiceli). To account for the chance of a prospect bust I reduce their value by a factor of the bust percentage, taken from the table above (% Zero WAR or less). It isn’t perfect, but seems reasonable, I’m happy to discuss in the comments.
Dansby Swanson (worth $137.2M) – to Atlanta
- #10 prospect currently (on MLB.com)
- Worth 15.6 WAR on average in years 0-6
- Arrives in majors in 2017
- 33% of value in years 0-3 (at 2018 cost per WAR) – 5.2 WAR – $45.76M
- 67% of value in years 4-6 (at 2021 cost per WAR) – 10.4 WAR – $105.04M
- Bust chance of #10 hitting prospect – 9%
- Estimated total value – $137.2M
Aaron Blair (worth $14.85M) – to Atlanta
- #61 prospect currently (on MLB.com)
- Worth 3.4 WAR on average in years 0-6
- Arrives in majors in 2016
- Assume only lasts 3 years in majors (due to low WAR total)
- 100% of value in years 0-3 (at 2017 cost per WAR) – 3.4 WAR – $28.56M
- Bust chance of #61 pitching prospect – 48%
- Estimated total value – $14.85M
Gabe Speier (worth $negligible) – sorry Gabe – this trade wasn’t about you.
Final value totals
- Shelby Miller – $98.5M
- Ender Inciarte – $172.9M
- Aaron Blair – $14.9M
- Dansby Swanson – $137.2M
- TOTAL – $325M
DIFFERENCE IN VALUE – $226.5M
There are a number of obvious caveats here. Miller could be better than this, Inciarte may not be that good, Swanson may never make it, Blair may never make it. However, at this moment, these are some of the values that you could reasonably ascribe to these assets. This is a staggering loss for Arizona. In what business can you lose $225M dollars in one transaction and keep your job? By this rather flawed measure, the Braves have just increased the value of their organisation by $225M. That pays for half a new stadium. Or Jason Heyward’s recent contract. Or the next 3 years of performance of Mike Trout (Trout is seriously valuable). I realise that the money can’t be accessed like that, but still, wow. Dave Stewart might be using his gut feeling when making deals, but he’d better start listening more to his analytics department or he’s liable to get robbed again.
A lot of the inspiration (it wasn’t plagiarism, honest) for this article came from Craig Edwards and his piece on “Attempting to rationalise the Shelby Miller Trade”. I just took it a different way. Thanks to Craig though! You should read it – http://www.fangraphs.com/blogs/attempting-to-rationalize-the-shelby-miller-trade/
UK based Braves fan. Obsessed with all baseball. Can also explain why cricket is excellent. Background in Physics and Medicine.