40 in 40: Edwin Diaz

When you think “Mariners starting pitching prospects,” what comes to mind? Nick Neidert, winner of the organization’s 2017 Minor League Starting Pitcher of the Year award — oh wait. Max Povse? Andrew Moore? Moore won 2016’s Minor League award, but do Moore or Povse even count as prospects any more? Sam Carlson is probably the most exciting, but he’s just 19.

What about the guy who won both 2014’s and 2015’s Minor League Starting Pitcher of the Year award? What happened to him?

It turns out that sometime in 2016, the organization decided to turn him into a relief pitcher. Shortly after that, he made the jump from Class AA Jackson directly to the Majors. And shortly after that, he started doing this with a fair amount of regularity:

With the utter dearth of starting pitching that the Mariners are currently experiencing, it’s easy to look at Diaz and wonder where he might be now with another year and a half of starter development under his belt. It’s important to remember, however, that he was far from a guarantee. Dipoto is on record as saying the team wasn’t confident that Diaz would be able to develop a strong third pitch, which would limit his ceiling as a starter.

And after Diaz’s rookie season in 2016, nobody cared about the potential that was Edwin Diaz: Starter. Edwin Diaz: Rookie Closer posted a K/9 of 15.3. Only 5 pitchers in all of MLB history had posted a higher K/9 in a season with at least 50 innings pitched.

So it was no surprise that Diaz went into 2017 with sky-high expectations. The question wasn’t “Will Edwin Diaz be good?” The question was “Will Edwin Diaz be historically good again?” Unfortunately, the answer was “no.”

The Mariners had a horrendous start last year, and Diaz was part of the problem. Through 16 games, his 15.3 K/9 from 2016 had become an 11.9. His 2.6 BB/9? It was up to almost 6.0. His velocity didn’t change. No, based on this chart from Brooks Baseball, it was his fastball’s horizontal movement that was different. It was about 15% less than what it had been in 2016 — a drastically significant difference.

As you can see, the black line for 2017 is well above the line for 2016. It’s not clear what could be causing this change. The spin rates on his fastball for 2016 and 2017 were virtually identical — 2289 RPM in 2017 and 2293 RPM in 2016.

Scott Servais indicated that Edwin’s struggles were due to some bad mechanics. He might have been right — Diaz did improve significantly after being temporarily pulled from the closing role on May 17, and finished with an overall above-average season. As you can see in the chart above, however, the movement didn’t improve. It looks like Edwin just learned to adapt to slightly diminished stuff, rather than improve the stuff.

Based on how the Mariners look to be positioned heading into 2017, the team will probably need Diaz to look more like his 2016 self in order to have a real shot at the postseason. There’s room for Pretty Good 2017 Edwin Diaz on any MLB team. The Mariners will need Historically Excellent 2016 Edwin Diaz.

There are a few guys who could step in should Edwin falter — Juan Nicasio and Nick Vincent are obvious candidates — but each of Diaz’s missteps will push the M’s further from a playoff spot. It’s an enormous amount of pressure to put on someone who will turn 24 just before the season, but that’s where we are, and we don’t have much of a choice.

It’s hard to find an easier guy to root for. I want Sugar to do well for the Mariners. But I also want Sugar to do well for more of these moments:

This is what makes the Mariners the Mariners. This is why 2018 will be fun, even if the team doesn’t make the playoffs. The unbridled emotion, the unapologetic personalities, the aesthetic of giving a shit.

If all goes well for Edwin Diaz and the rest of the Mariners, we won’t have to rely on personalities and fun to get us through the year. But there are worse fall-backs.

Go M’s.