After Corbin Carroll walk-off, it's time for the Mets to be concerned about Edwin Diaz

In what felt like a blink of an eye, the New York Mets turned what was a 4-0 deficit and looked like a loss to the red-hot Arizona Diamondbacks into a 5-4 lead. All of a sudden, the Mets seemed poised to take the first two games of a crucial three-game set in Arizona, assuming the bullpen could do its job. Unfortunately, the Mets bullpen could not seal the deal.

Huascar Brazoban, Danny Young, Reed Garrett and Phil Maton kept the Diamondbacks off the board through 3.2 innings of work, and the Mets turned to their star closer Edwin Diaz for a four-out save. Maton left a runner at first base, but there were two outs in the eighth inning with the Mets holding onto a 5-4 lead. All Diaz had to do to send this game to the ninth was record one out. He failed to do so.

He'd walk the bottom two hitters in Arizona's order, loading the bases for the suddenly raging hot Corbin Carroll. Diaz hung an 0-1 slider right over the heart of the plate, and Carroll made no mistake, sending it over the right-center field wall for a grand slam. What was a 5-4 Mets lead turned into an 8-5 deficit. The Diamondbacks would win by that final score.

The loss dropped New York to 3-3 on what could be a season-defining road trip. A .500 record six games in considering the quality of competition they've faced isn't so bad, but they realistically should be 5-1. Diaz is responsible for two of those losses, giving up a walk-off home run in Sunday's series finale against the San Diego Padres. His late-season struggles are giving the Mets legitimate reason to be concerned about him down the stretch.

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Edwin Diaz gives Mets reason to be concerned after another blown save

In 2022, Diaz was on top of the baseball world. He was untouchable on the mound and had the best closer entrance in the game to boot. He wound up missing all of 2023 after tearing his patellar tendon in his right knee celebrating a win in the World Baseball Classic, and things haven't quite been the same in his first year back.

Diaz missed some time due to a shoulder injury, he was suspended for sticky stuff and hasn't looked nearly as dominant on the mound. Wednesday's game was a prime example of that.

The 30-year-old has a 4.30 ERA in 39 appearances and 37.2 innings of work this season. He has converted just 14 of his 20 save opportunities and has taken three losses. What's most concerning about Diaz isn't even the numbers themselves, it's how he has pitched.

His command has felt off all season long, and the statistics back that up. He has allowed seven home runs in just 37.2 innings of work, allowing home runs at a higher rate than he has any season of his career outside of his disastrous 2019 campaign. His 9.8 percent walk rate is the third-highest mark of his career and his highest in a full season (excluding 2020) since 2017. So he isn't throwing enough strikes, and the strikes he is throwing happen to be very hittable.

Most of his issues seem to be coming from the pitch Carroll hit out on Wednesday and Merrill won Sunday's game with, his slider. Opponents are hitting .213 against Diaz's slider this season according to Baseball Savant which might seem solid, but it's 99 points higher than the .114 average they had against that pitch in 2022. To show just how ineffective his slider has been relative to his fastball, Diaz has given up five home runs using his slider. He has surrendered a total of eight hits against his fastball, and that's even with his velocity being down. The comparison is stark, yet he's using his slider over nine percent more than his fastball.

"My slider is floating in the zone,” Díaz said, bemoaning a mechanical issue that has him falling toward third base rather than pointing his body in a straight line to home plate.

Diaz has still shown great stuff in many of his outings this season and is hard to hit when he's locating. He just simply isn't locating at all. Walking the eight and nine hitters to get to the hottest hitter in the lineup who would eventually hit a grand slam is simply unacceptable.

Unfortunately for the Mets, they realistically go where Diaz takes them. They're at a talent disadvantage in their bullpen, especially if Dedniel Nunez is hurt again. The Mets have little choice but to stick with Diaz as their primary closer, even if there's reason to be concerned about him not being good enough. With the team now 4.0 games back of the third Wild Card spot with 29 games to go, the Mets will need him to somehow figure it out ASAP.