Stay or Go: Should Mets re-sign Edwin Diaz?

For Edwin Diaz, his four-year Mets career is the living embodiment of a "how it started vs. how it's going" meme.

It started for Diaz with a disastrous first season in Queens in 2019, when he posted a 5.59 ERA (4.51 FIP) and 1.37 WHIP while allowing a whopping 15 home runs in 58 innings over 66 appearances.

In 2019, it seemed that every time Diaz made a mistake, it was hit out of the ballpark. And while there was some bad luck involved, he was simply very bad. At times, he had no idea where his slider was going, which is a huge issue for someone who only features two pitches.

That Diaz and the now twice-disgraced Robinson Cano came over prior to the 2019 season in a blockbuster deal that sent Jarred Kelenic to the Seattle Mariners added to the vitriol he received for his struggles in his debut season as a Met.

How's it going now for Diaz?

While many focus on Diaz's remarkable 2022, which we'll break down in a bit, he has been terrific since 2020.

In 150.1 innings over 150 appearances over the last three seasons, Diaz has a 2.27 ERA (1.78 FIP) and 0.99 WHIP while striking out 257 batters -- an eye-popping 15.4 per 9.  

During the past three seasons, Diaz has allowed eight home runs total after giving up 15 in 2019.

Diaz was an All-Star in 2022 and will receive not only Cy Young votes but probably get some MVP votes for how he performed this season. His entrance song, "Narco," -- featuring infectious trumpets -- has also become a cultural phenomenon. So it's going well.

I'll also take a quick second here to note that I wrote before the 2020 season why Diaz was primed for a bounce-back season, wrote in September 2020 that Diaz was good and could be a huge part of the Mets' future, wrote in March of 2021 that it was time for Mets fans to realize that Diaz was dominant and reliable, and wrote on May 6 of this year that it was time for the Mets to extend Diaz.

So what Diaz has become in Queens has certainly not been a surprise to this writer.

WHY IT COULD MAKE SENSE TO LET DIAZ GO

Letting Diaz walk wouldn't make much sense at all, but I'll play devil's advocate and write this section anyway.

With many relievers, there's a risk of year-to-year volatility, even when it comes to the most dominant ones with the nastiest stuff.

We've seen it recently with Craig Kimbrel and -- to a lesser extent -- Josh Hader.

With Diaz, though he has ranged from being very good to historically good in six of his seven big league seasons, there has to be at least some concern about his long-term projection because of how reliant he is on his two-pitch mix.

We've seen that when command of his slider goes, it could be tough sledding for him. But with Diaz really harnessing his slider now and keeping it low in the zone more often than not, the main worry here would be him losing a good deal of zip on the fastball that is his other weapon.

But Diaz will be entering his age-29 season, so he should still have a handful of prime years left. And his fastball velocity in 2022 (it averaged 99.1 mph) was the highest of his career. His average slider velocity (90.8 mph) was also the highest of his career.

One other concern could be an injury taking Diaz out, but he's been one of the most durable relievers in the league since his rookie season with the Mariners in 2016.

That takes us to the money and years it might take to re-sign Diaz. 

There has been some speculation that Diaz could get $100 million, perhaps on a five-year deal. That's steep and would be record money for a closer. But it's hard to overstate how important a dominant and reliable closer is to a team with World Series aspirations.

WHY IT COULD MAKE SENSE TO KEEP DIAZ

How much time do we have?

Simply put, Diaz is the best closer in baseball, the best closer the Mets have ever had, and is showing no signs that he'll slow down any time soon.

To put what Diaz did in 2022 into perspective is close to impossible, but let's just say that what your eyes were telling you as he overmatched hitter after hitter jives with what the advanced numbers show. 

Via Baseball Savant, Diaz was in the 100th percentile in 2022 when it came to xBA, strikeout rate, xSLG, xERA/xwOBA, and whiff rate. He was in the 99th percentile in fastball velocity, the 97th percentile in chase rate, the 96th percentile in average exit velocity, and the 93rd percentile in barrel percentage. 

Getting into the more traditional numbers, Diaz had a 1.31 ERA (0.90 FIP) and 0.83 WHIP while striking out 118 batters in 62 innings -- a ridiculous 17.1 per nine.

Diaz gave up just three home runs in 2022, with the last one he allowed coming on May 12.

Over his last 34 appearances (in 34.2 innings), Diaz gave up two earned runs (an ERA of 0.52) and had a FIP of 0.14! During that span, he held opposing hitters to a .122/.183/.139 triple slash while striking out 65 and walking seven.

Diaz was also nails in both of his postseason appearances, tossing 2.2 scoreless and hitless innings while walking none and striking out two.

It should also be noted again that what Diaz did in 2022 wasn't a new development. He has been a dominant force since 2020.

Diaz has also embraced everything that comes with pitching in New York and has a strong interest in being back.

Considering how a player might perform in a certain market can sometimes be overblown, but sometimes it matters a lot. And one of those times is when you're talking about a closer in the New York market who is pitching for a team with World Series aspirations.

In the case of Diaz, he has not only embraced the pressure but thrived under it.

VERDICT

This is probably the easiest call the Mets will have to make this offseason.

With Edwin Diaz, they have a truly elite closer in his prime who possesses some of the nastiest stuff in baseball. And Diaz wants to be here.

Getting Diaz extended should be something the Mets can get done with relative ease, and it's hopefully a deal they can get out of the way during the exclusive five-day negotiating period they'll have with Diaz after the World Series ends.