Joe Blanton's slider just made him $4 million

I was perusing some reliever leaderboards about a month ago, and a funny thing happened: I saw Joe Blanton's name on it. After aggressively rubbing my eyes multiple times to make sure I wasn't seeing things, I decided to sort the leaderboard by another metric. Another funny thing happened — there was Blanton's name again. No matter which of my favorite reliever-valuing metrics I used to sort the leaderboard, Blanton kept coming up.

All joking aside, I will only make fun of a professional athlete with the knowledge that he is significantly better at his sport than I, or over 99% of the population, will ever be. But I was still surprised to see that someone who didn't appear in the MLB at all in 2014 and was last seen posting a 6.04 ERA/ 5.12 FIP with the Angels was not only back in the league, but thriving.

So how good was Blanton last year? I mentioned that his name came up no matter how I sorted the leaderboard. Out of all qualified relievers in 2015, Blanton finished in the top 25 in ERA, FIP, xFIP, and SIERA. Only five others can claim the same thing, and you could say they're pretty good at what they do: Aroldis Chapman, Dellin Betances, Andrew Miller, Zach Britton, and Mark Lowe. Pitching out of the bullpen for the first time, Blanton posted a career-high 27.0 percent K rate and 21.7 percent K-BB rate, to go along with the aforementioned ERA and ERA estimators (2.04 ERA/2.56 FIP/2.84 xFIP/2.59 SIERA)* that were also career bests.

Note: Blanton made four starts that were left out of these stats; Blanton will probably be exclusively relieving in 2016.

So what changed with Blanton as a starter and as a reliever? Well, the most obvious thing is that Blanton changed from a starter to a reliever. The typical pitcher will see an improvement in effectiveness just from the switch, of which Blanton was no exception, and Blanton also experienced the typical velocity bump (fastball velocity up 1.4 MPH from 2013). However, typical starters-turned-relievers don't see this vast of an improvement. Blanton was clearly doing something different than what he was doing during his exclusive starting days. Take a look at his pitch selection:

Blanton morphed his slider and cutter into one pitch, combined their usage, then more than doubled that percentage. His fastball usage remained steady, and the uptick in sliders resulted in fewer curves and change-pieces.

As you'd expect, pitchers throw their best pitches more frequently than their lesser ones (or at least they should), and Blanton threw his slider over 30 percent of the time because it was really, really good. How good? According to FanGraphs' pitch type linear weights, Blanton's slider as a reliever, on a per-pitch basis, was more effective than those of every single pitcher in the MLB not named Jorge De La Rosa, including both starters and relievers. De La Rosa also threw his slider 0.3 percent of the time, all of which were probably his misclassified cutters, so it could reasonably be said that Joe Blanton owned the best slider in baseball last season.

Don't forget that these numbers are on a per-pitch basis, and Blanton threw his slider an astounding 31.6 percent of the time. Even as he ratcheted up the frequency of his slider and hitters came to expect it more and more, they still couldn't hit it. To explain how good his slider was in a practical sense, 76 plate appearances ended in a Joe Blanton slider last season. 33 of those ended in a strikeout, while only two went for extra-base hits, both of which were doubles. Hitters managed a paltry .400 OPS and 19 (yes, 19) wRC+ against his slider. He somehow only threw the slider in the zone an astoundingly low 36.0 percent of the time, but hitters kept chasing it out of the zone, to the tune of an astoundingly high 43.8 O-Swing rate. Translation: it didn't matter where Blanton threw his slider; hitters couldn't touch it, and those that did couldn't do anything with it.

As Neil Weinberg detailed in November, Blanton also drastically lowered his arm slot in 2015. This could either be another factor that led to Blanton's newfound dominance, or it could be linked to the effectiveness of the slider. Looking at both FanGraphs' and Brooks Baseball's pitch type data, neither the vertical nor the horizontal movement on Blanton's slider really changed from when he threw from a higher arm slot, but it's easily possible that the lower slot led to a more deceptive pitch or less separation from the fastball.

Regardless of the reason why, it is clear that Blanton is a much different pitcher than he was back in 2013, and the MLB contract and $4 million guarantee that he just received from the Dodgers speak to that. Blanton doesn't even need to be close to how good he was in 2015 in order to justify this contract, and he provides value in other ways from most relievers in that he can pitch multiple innings if needed.

$4 million is in a weird no-man's land for salaries: It's large enough that it isn't exactly a no-risk type of contract for a team, and the deal will largely be seen as a failure if Blanton doesn't pan out; but it's also a small enough guarantee that the player will almost assuredly exceed its value if he just manages to stay on the roster for entire season, especially for a team with playoff hopes like the Dodgers. In the end, though, money isn't really an objection for the Dodgers as long as it isn't of the multi-year variety, and this contract can be seen as an interesting low-risk gamble for a team that missed out on bigger names such as Darren O'Day and Aroldis Chapman earlier this offseason. While Blanton probably isn't going to be as good as those two in 2016, with this contract, he doesn't need to be.

. . .

Austin Yamada is a contributing writer for Beyond the Box Score.