How Good Have Masahiro Tanaka's First Four Starts Been?

At the beginning of each and every baseball season, we marvel over some of the incredible early season rate stats that players post. Whether it be a 2.500 slugging percentage out of Mike Morse or a 0.00 K/9 from Kevin Correia (which might actually be true), it's fun to look at these stats that we all know are, unfortunately, unsustainable.

After his first start, everyone got a good chuckle out of some of Masahiro Tanaka's silly early rate stats. He had a very good 10.29 K/9 paired with an ign'ant 0.00 BB/9. You could say that'd get the job done. But it was only for one start.

However, we are now four starts into the Reign of Tanaka, and he's still dropping some stupid sauce on the statistical world. He was also at the top of our Rookie of the Year standings prior to Tuesday's start against the Red Sox. Here's how Tanaka ranks in a few categories in comparison to his counterparts in the A.L:

Here are just a few definitions for the stats in the table above. FIP is fielding independent pitching, and is a measure of a pitcher's effectiveness based solely on strikeouts, walks and home runs allowed. xFIP is that same thing, except it is adjusted based on the ballpark in which the pitcher is pitching. O-swing percentage is the percentage of pitches outside the zone at which opposing batters swing. Contact percentage is the percent of swings opposing batters take in which they make contact. SwStr percentage is the percentage of strikes from the pitcher that come via swings and misses.

What does this mean for Tanaka? It means his splitter is the new dirty daddy of the American League. Batters are chasing it outside of the zone at a ridiculous rate, and this results in a lot of swings and misses.

Far and away, the best statistic above for Tanaka is BB/9. His control has been amazing. His strikeout-to-walk ratio is currently at 35:2. It helps that people are currently yacking at every pitch he tosses out of the zone, but the man is just toying with hitters at this point.

All of this isn't to say that these numbers won't change as we progress deeper into the Reign of Tanaka. Once teams start seeing him for the second time, they might have a better handle on what his stuff does. That's not saying a lot because they seem largely clueless right now. Some regression should be expected with his o-swing percentage and contact percentage, but even that regression will be far better than league average.

If you're going to look for a reason to be concerned with Tanaka, you're not going to find much. But, you wouldn't be completely without ammo.

One statistic that indicates that Tanaka's ERA will eventually regress a bit is his strand percentage. This stat simply measures the number of runners that a pitcher leaves on base. Through those four starts, Tanaka has stranded 87 percent of base-runners. This is about 15 percentage points above the league average, which is in the low 70s. This is unsustainable even for the best pitchers. Last year, Yu Darvish led the league in the category at 83.9 percent, and only eight pitchers finished higher than 80 percent.

The thing in Tanaka's favor here is that pitchers that record a high strikeout rate can have higher strand percentages than those that don't. That's why it's not a shock that Darvish led the league or that Clayton Kershaw finished fifth. Either way, though, the likelihood that Tanaka's strand rate stays where it is now is slim.

The other statistical category in which Tanaka has struggled is his home run to fly ball ratio. The league average hovers around 10 percent; Tanaka's ratio is at 18.2 percent. Throughout the course of a season, that would be, in technical terms, a pooey number.

The thing about this, though, is that it also will regress toward the mean. According to the FanGraphs explanation page for this stat, 13.0 percent is considered "awful." Anything greater that should be considered an outlier. The long-balls will start to dwindle for Tanaka, and that should help cancel out a bit of the regression with his strand rate.

I don't want all of this to sound like I'm saying Tanaka is better than Kershaw or Jose Fernandez (swoon), or that he ever will be. I'm more just trying to show how great of a start Tanaka has had and provide some validation behind the stanky numbers he has put up so far. Some regression should be expected, but this man is going to be a very good starter in the majors for some time to come.