Paul Sewald Makes Immediate Impact on Diamondbacks Bullpen

Since the closer returned on May 7th, the D-backs bullpen has been vastly improved from earlier in the season.

May 15, 2024; Phoenix, Arizona, USA; Arizona Diamondbacks pitcher Paul Sewald (38) celebrates with catcher Gabriel Moreno (14) after beating the Cincinnati Reds 2-1 at Chase Field. Mandatory Credit: Matt Kartozian-USA TODAY Sports | Matt Kartozian-USA TODAY Sports

Paul Sewald has quickly become a fan favorite of the Arizona Diamondbacks. The closer has changed the team and bullpen for the better ever since the team acquired him from the Mariners last July. As was written about plenty last year, once he arrived, the bullpen became far better.

Sewald is a veteran leader and closer that can handle the intensity of pitching in the 9th inning every game. The reliable closer is also one of the nicest players on the team and recently started a charity effort to help at-risk children and families.

When Sewald was injured earlier this season, the Diamondbacks bullpen was a mess. They struggled to hold leads, keep games close, and everyone was pitching out of their role. However, since May 7th, when Sewald returned, the D-backs pitching staff has completely changed for the better.

Not only can you see that with the eye test, but the advanced stats all say that the bullpen is completely different than it was before Sewald returned.

The bullpen ERA from Opening Day to May 6th was 4.44 and was ranked 24th in baseball. Since Sewald came back May 7th, it's 4.13 and ranks 17th.

Win Probability Added "quantifies the percent change in a team's chances of winning from one event to the next" per MLB. From Opening Day to May 6th, WPA was -1.00 and ranked 25th. This means that the unit was swinging games too improbable for a win.

However, since May 7th, the bullpen WPA is 0.96 and that ranks 14th in baseball.

Wins Above Replacement measures a player or unit's value to winning above the average baseball player or unit. From Opening Day to May 6th, the bullpen ERA over those 35 games was just 2.0 WAR, ranked 21st in MLB.

Since May 7th, in the 25 games since, the bullpen has garnered 2.8 WAR and rank tied for 11th.

Their FIP from Opening Day to May 6th was an unsightly 4.08, 21st in MLB. However, since Sewald came back May 7th, it's dropped all the way down to 3.76, good for 8th in baseball.

They had 26 meltdowns over 35 games from Opening Day to May 6th, which was the fourth most in baseball. Since May 7th, they have had just 10, the fourth fewest.

As for shutdown outings, the bullpen had 30 of them between Opening Day and May 6th, which was 19th in MLB. Since May 7th, they have 22 over 25 games, tied for 8th best in baseball.

As the stats show, Paul Sewald has made an immediate impact on the Arizona Diamondbacks bullpen since he returned May 7th. Without him, this bullpen would be in a far different place. Plus, the Diamondbacks would not be 14-12 since May 5th if it weren't for the return of Sewald and putting relievers back in their correct spot.