How Much Does Rakuten Believe Kazuya Fujita's Defense is Worth?

The Rakuten Golden Eagles have re-signed (he did not exercise his domestic free agent option, so instead of just agreeing to a contract for the year, they extended him) starting 2nd baseman Kazuya Fujita to a 3 year deal worth 240 million yen, or about 80 million yen a year. Fujita is mainly known for his defense, and in my opinion, is the best defensive 2nd basemen in Japan, and possibly the best defender in the NPB as a whole, regardless of position. However, the NPB doesn't have the advanced defensive metrics (that are flawed as well) we easily access when looking at MLB players. The only thing close is range factor, which is crude, but does like Fujita a lot. In this post, I wanted to take a stab at estimating how valuable, in terms of money, Rakuten thinks Fujita's defense is.

The first step in doing this is to estimate how valuable the other parts of his game are, which should be easier. Defense is the toughest to quantify statistically, so we should look at how valuable his offense is, and assume that Rakuten, using simple metrics, value his offense about the same. In 2013, Fujita was worth -9.84 runs offensively against average but 11.21 runs against a fictional replacement level of .32 winning percentage. For the rest of this post, I'll be using average as the baseline instead of replacement, because it is easier, and a little less confusing when it comes to position players, as all three aspects of the game will be weighed against (Pacific) League average. Fujita's offense has been declining, as these are his adjusted OPS's over the last three seasons against league average:

112 OPS +, 100 OPS +, 91 OPS +
 
I think it is safe to say that Fujita, at age 31, will probably keep declining, or at least hold serve. A safe estimate for the three year contract would be Fujita being 10-15% worse than league average when it comes to batting, probably around 10-12 runs below average over full seasons. With positional adjustment, we can convert that to 8-10 runs a year.

Fujita is also worth nothing when it comes to the basepaths, with a grand total of 22 steals in his entire career. Out of the 68 qualified batters in the Pacific League in 2013, his 3 steals were tied for 33rd best in the league. He's not quick, but he isn't especially a baseclogger either, so we will conservatively estimate that he is worth 1-2 runs less than average per year.

So if Fujita was an average defender, we would estimate that he would be 9 to 12 runs worse than league average over a full season. A MLB comp might be someone like Jose Altuve, someone who plays 2nd with average defense (according to DRS), with below average offensive value and not much baserunning value. However, no one thinks Fujita is an average defender, and that is the purpose of this post, as we are attempting to see how much Rakuten thinks the defense is worth. However, there is another step that we haven't gotten to yet, and it may be the toughest. While we have an estimate of how much Fujita is worth, without defense, when it comes to wins and losses, we haven't converted that into money yet. In the MLB, a win is generally considered to be worth about 5 million dollars, or perhaps 6-7, depending on who you ask. However, we need to convert this into NPB salaries (and adjust for currency as well). So we need to look at how much NPB teams are paying for players, and more specifically, runs and wins.

According to the salary data collected by Yakyu Baka, the average NPB player made about 36.55 million yen, or about 365,000 American dollars (for the purpose of this post, we are assuming that 100 yen is 1 dollar, even though it is a little more than that. However, I'll keep most of the discussion to yen). So Fujita will make over double what the average player will make, but it seems far too simplistic, especially not taking in account things like service time and leverage to say that Rakuten values him twice as much as they would a league average player.

First, I wanted to look at the domestic free agents signed in 2013, and see if their 2013 WAAs had any predictive value when it came to what they will be paid in 2014. I just used a simple wins above average using runs created offensively, and just ERA WAA (split up between leagues) for pitchers.

The first problem we encounter is that there are only 8, which is really too small of a sample size to make any conclusions. Secondly, the worst player according to the simple WAA is the most expensive player, paid mainly for his past success. For these reasons, it seems tough to use those free agent contracts to project value.

So it may be more helpful to look at how Rakuten values wins and dollars, or at least how much they paid in 2013 for players versus the output they got. I limited the look at 7 individual players, the 5 foreign players and the two players on the team that were former MLB players. These players would most simulate "open market signings", which we are assuming Fujita is.

So Rakuten paid 622 million yen for the 7 players for 4.9 Wins Above Average or roughly 126 million yen per win over average. It should be noted that Rakuten has offered Masahiro Tanaka a 800 million yen a year contract to stay with the team after a 5.4 WAR season. This is a little over the rate of the other players, but at 148 million yen per win, isn't too far off (and it is safe to say that Tanaka has more leverage than Fujita had and Tanaka holds more sentimental value to Rakuten).

So with the 8 free agent signings in the NPB this year having a wins above average of just .51 total, and about 1068 million yen dolled out for the 8 players, Rakuten was much more efficient with their "foreign players" than the teams that dipped in the domestic free agent pool in 2013 (assuming these players don't perform much better in 2014). This should be kept in mind when discussing Fujita's contract, as it seems like NPB free agents were well overpaid.

If we keep the guesstimates about Fujita's non defensive value that we made above, and we assume that Rakuten is willing to match their 126 million yen per win above average, then Rakuten values Fujita's defense as worth anywhere from 15-18 runs per season, or about 189 million yen to 227 million yen per year (without subtracting what an average player would get anyway).