How Important are Closers in the Postseason?

Jordan Romano, closer for the Blue Jays; CC by License 2.0

October baseball is right around the corner as teams compete to snag a postseason spot down the stretch of the regular season. Every team has to make sure their roster is in optimal condition to go head-to-head against the league’s best, and a large part of that is solidifying the closer role coming out of the bullpen. Starting pitching can carry a team through the regular season, but when it comes to postseason play, an effective closer is what separates the good teams and the teams with legitimate World Series chances. Just last year, Astros’ closer Ryan Pressley helped secure the final two games of the World Series going 2.2 innings allowing only 1 hit, 2 Ks, and no walks. And in 2021, Braves’ closer Will Smith stepped into high-leverage situations in the 9th to close out Games 3 and 4, aiding his squad in key moments that helped contribute to the World Series title. It’s obvious that an effective closer is a nice luxury for teams with World Series hopes, but postseason bullpens have become more of a necessity over these past few years. It’s no secret that starting pitchers have gradually declined in their ability to pitch deep into games like starters of old. However, it gets even worse when we take a look at how deep starters have made it into postseason starts versus regular season starts.

If we take a look at the sheet above, it is clear that when it comes to the bright lights of postseason play, starters have generally been pulled earlier than they were during the regular season. Despite 2021 All-Star Walker Buehler finishing the regular season 2nd in the majors for innings pitched, he pitched almost 2 entire innings less on average in his starts during the postseason. Another pitcher of note here is 2022 Cy Young candidate Aaron Nola, who also finished his regular season 2nd in the majors for IP, but pitched more than an entire inning less per start in October. Teams in the postseason are turning to their bullpens earlier than ever, making the team’s closer that much more important.

As we sit here on September 12th, the field for postseason play is far from completely solidified. However, we have a clearer picture today than we have all season. In this article, I look to break down some of the high-level closers that we are likely to see in just a few weeks, and what role they might play in their team’s success come October.

*data/chart via FanGraphs*

Team: Toronto Blue Jays

Closer: Jordan Romano

We start this list with the closer who leads the pack (among the field) in regular season saves at 34, Blue Jays’ closer Jordan Romano. Romano started to receive some well-deserved recognition in 2022 when he got his first All-Star nod, and he followed it up with his 2nd consecutive nod this season. However, there is some cause for concern when you look deeper into his numbers. Romano has the highest SIERA and xFIP of any closer in the field. Both stats speak to pitcher performance outside of components that are out of the pitcher’s control like fielding. His higher SIERA and xFIP numbers, especially in comparison to his ERA and FIP respectively, tell us that Romano has been slightly propped up by good defense and luck in general. Luck tends to run out when it comes to the postseason, so we’ll see if Romano can keep up the pace.

Team: Arizona Diamondbacks

Closer: Paul Sewald

After realizing they were in a position to make a run at the postseason for the first time since 2017, the D-Backs went out at the trade deadline and brought in some much-needed bullpen help in the form of former Mariners’ closer Paul Sewald. Something interesting to point out when it comes to Sewald are the impressively low barrel and hard-hit percentages. His 5.1% barrel rate and 28.7% hard-hit rate are his lowest marks since 2020 when he was still a Met, which is a good sign considering Sewald is already in his age 33 season. Sewald is a closer who allows soft contact which is always a good thing, and it will serve him well when the big moment arrives.

Team: Milwaukee Brewers

Closer: Devin Williams

Much like Jordan Romano, Devin Williams has made the All-Star team for the NL two consecutive years now. Unlike Romano, Williams is likely the best closer of this bunch. Amongst the field, Williams outranks everyone in more than half of the categories considered (SwStr%, fWAR, WHIP, BABIP, FIP, ERA, H/9, HR/9, K/9). When he is on, there is no better closer in baseball than Devin Williams. His pure dominance is evident when you look at his H/9 at 4.44, more than 2 whole hits less per 9 innings than any other closer in the field. The only knock on Williams would be his inability to limit free passes, leading the way with 4.10 BB/9. If Williams can keep it under control in the postseason, he’s going to be a must-watch TV come the 9th inning.

Team: Houston Astros

Closer: Ryan Pressly

As I mentioned before, one of the stars in last year’s World Series was the Astros’ veteran closer Ryan Pressly. Despite being one of the most experienced closers headed into October, Pressly wishes he could return to that form he saw just a season ago. Almost every single stat looks worse for Pressly this season than it did in 2022. Not just that, but Pressly is posting career worsts in barrel and hard hit percentage, while also posting his worst FIP and strikeouts per nine innings since putting on the Astros jersey in 2018. One good thing that can be taken away from Pressly’s ‘23 campaign is that he’s allowing a career low in walks per nine (1.68), and limiting walks in postseason play is one of the most important factors when it comes to closing. Pressly hopes that once the pressure is at its highest level he can return to his dominant form of the past, or he could continue to unravel at age 34.

Team: Atlanta Braves

Closer: Raisel Iglesias

A closer that floats more under the radar would be another veteran in the form of Braves’ closer Raisel Iglesias. When the Braves traded for Iglesias last season, he provided an additional presence in the bullpen behind future Hall of Famer Kenley Jansen. But Braves fans remember all too well when Iglesias got just one out after 3 hits and a walk during game 4 of the NLDS last year. Flash forward to this year, and as Kenley moved on to Boston, Iglesias stepped up into the primary closer role. What stands out for Iglesias is his 53% swing percentage, which ranks out highest among the field and is complimented nicely by a 35.2% chase rate according to Baseball Savant, which finishes out in the 98th percentile. If his pack-leading 7.77 hits per nine innings can creep down for the postseason, Iglesias could come up big for the former World Series champs.

Team: Minnesota Twins

Closer: Jhoan Duran

The closer ‘closing’ out this list is the youngest of the group, the Twins’ 25-year-old closer, Jhoan Duran. After making his major league debut in April of last year, Duran has done nothing but dazzle fans with an average fastball of 101.8 MPH according to Baseball Savant. This puts Duran into a category of his own with the highest velocity in all of baseball. That alone would be enough to make a case that Duran is the best closer of the bunch, but his elite velocity paired with the lowest SIERA and xFIP of any closer in the field tells us that Duran is truly something special. Higher marks for his ERA and FIP respectively tell us that the team around him isn’t doing much to help him out. If the Twins can lock down on defense and limit the mistakes, then Duran could be the most anticipated closer to watch in October.

In this article, I broke down some of the most exciting closers we expect to see in just a few weeks. However, as I led off with, this year’s postseason bracket is far from a sure thing. If the Reds or Giants can rattle off a nice stretch to end the regular season, then Reds’ closer Alexis Diaz and Giants’ closer Camilo Doval will be plenty of fun to watch as the 9th inning rolls around. As an Orioles fan myself, seeing closer and Cy Young candidate (prior to injury) Felix Bautista return for playoff baseball is not completely out of the question. Closers bring such a unique skill set to the table, pitching in the highest-leverage situations to get their team a win. Can’t wait to watch these impressive closers put on a show this postseason.

Sources:

Fangraphs

Baseball Savant

Baseball Reference

MLB