National League Wild Card Preview: Arizona Diamondbacks vs. Milwaukee Brewers

After missing out on the postseason last year, breaking a four-year streak, the Brewers are back in the playoffs this year. They’ve been the model of consistency over this past half decade; they are the only other team apart from the Astros and Dodgers to have won at least 86 games in each of the last six full seasons. But for all that regular season success, they’ve only won one postseason series during this stretch, a Division Series back in 2018. They have one of the strongest run prevention units in baseball and are hoping that will carry them deep into October.

Milwaukee’s first-round opponent, the Diamondbacks, will be making their first playoff appearance since 2017. They’re breaking out of a long rebuilding cycle a little ahead of schedule thanks to the phenomenal rookie campaign of Corbin Carroll. On paper, they’re significant underdogs when compared to the dominant arms the Brewers can bring to bear, but they’ve got enough young talent to make some noise as a surprise contender:

As this preview was being written, news broke that Brandon Woodruff will miss the NL Wild Card series with a shoulder injury; his availability for the rest of the postseason is “up in the air” according to manager Craig Counsell. Counsell hasn’t announced who will start Game 2 — Freddy Peralta last pitched on September 24, so he’d be fully rested — but I’m sure that decision will wait until after the outcome of Game 1 has been determined. If the Brewers win the opener behind Corbin Burnes, they could use Wade Miley in Game 2 to try and steal a win. That would allow them to save Peralta for a potential decisive Game 3, or for Game 1 of the NLDS if everything works out for them on Wednesday.

On the Diamondbacks’ side of things, because they were fighting for a playoff spot through the final weekend of the regular season, their rotation is a little out of whack to start the Wild Card round. They’ll start Brandon Pfaadt in Game 1, and then have their two top options in Zac Gallen and Merrill Kelly lined up to finish the series. For his part, Pfaadt has improved a bit as the season has gone on; he really struggled upon making his major league debut in May, but has put up a 4.32 ERA and a 4.06 FIP across five September starts that also included two shutout efforts.

The Woodruff injury shifts everything around, significantly changing the calculus for the Brewers and giving the Diamondbacks a much better chance of advancing to the divisional round. Here’s a look at the ZiPS Game-by-Game Odds for the series before and after the Woodruff injury:

Notably, the odds currently published on the site have Peralta lined up in Game 2 and Miley in Game 3. As you can see, the Brewers went from favorites in each of the three games to slight underdogs in the final two games of the series, where the pitching matchups swing in Arizona’s favor. This is a rare case where leading with their third best starter might end up working in the D-backs favor — provided they’re up for winning two back-to-back elimination games:

The overall series odds shifted significantly as well. Milwaukee entered this week with the second-highest chance of advancing to the Division Series among the Wild Card teams, but without Woodruff, the outcome of the series is now a coin flip. That’s a pretty dramatic shift in fortunes for both teams, with this series suddenly becoming the most evenly matched among the four Wild Card Series.

What would the odds look like if the Brewers chose to use Miley in Game 2 and Peralta in Game 3?

Game 2 would shift heavily in Arizona’s favor, while Milwaukee would enter Game 3 as a slight favorite. The overall series odds barely budge in this scenario, with the Brewers winning 50.8% of the time. It’s possible that this tiny advantage is worth the risk of holding Peralta back for Game 3, but I’d expect the Brewers to make the straight play and go with Peralta in Game 2 no matter the outcome of Game 1.

Behind the starters, the Brewers hold a significant advantage in the bullpen. Joel Payamps, Trevor Megill, and Hoby Milner have formed a solid bridge to All-Star closer Devin Williams and his unhittable airbender changeup. As a group, they had the ninth-best adjusted FIP in baseball this year and were even better during the second half, trailing just the Dodgers. If the Brewers can build an early lead, their relief corps is going to shorten the game very quickly.

Meanwhile, the bullpen is decidedly not a strength for the Diamondbacks. They traded for Paul Sewald at the trade deadline to give them a proven closer in the ninth inning; he was a little shaky in August (a 4.66 ERA in 9.2 innings that month) but got things back on track in September (2.25 ERA, 8 IP). Kevin Ginkel has proven to be a pretty good fireman behind Sewald, but the rest of the options in Arizona’s ‘pen look rather lackluster.

The run prevention extends beyond the pitching staff for both of these teams, as they’re both among the best fielding teams in baseball. No matter which metric you use, the Brewers rank either first or second in baseball, with the Diamondbacks are right behind them:

That kind of defensive prowess is a big reason why Arizona’s pitchers have outperformed their peripherals. When you break down the defensive performance on the individual level, only Willy Adames ranks in the top 15 on the Outs Above Average leaderboard, with +16 OAA at short for the Brewers. Christian Walker is at +12 OAA at first base for the Diamondbacks, but the majority of their proficiency comes from mistake-free play and solid contributions around the field.

Offensively, the Brewers are hoping a late season run-scoring surge will carry over into the playoffs. Over the first five months of the season, Milwaukee scored just 4.15 runs per game, one of the worst marks in baseball. During August and September, that mark jumped up to 5.16 runs per game. They can thank some key midseason acquisitions for that spark:

Mark Canha has been a key contributor for the Brewers since coming over from the Mets, particularly in a September that saw him slash .301/.387/.452 (132 wRC+). Carlos Santana has come up with some big clutch hits, and Josh Donaldson has found a way to salvage the tail end a completely lost season with three home runs across his first 10 games as a Brewer. He wasn’t acquired midseason, but William Contreras has been a huge boon for Milwaukee since coming over in the big Sean Murphy trade this past offseason. He ended the year on an 18-game hitting streak and has been one of the best defensive catchers in baseball. Beyond those newcomers, the Brewers have enjoyed a resurgent season from Christian Yelich. He isn’t back to his MVP-caliber level from half a decade ago, but his 122 wRC+ this year is the highest it’s been since 2019.

The Diamondbacks’s offense runs through Carroll — the rookie outfielder has hit .285/.362/.506 (133 wRC+), with 25 home runs and 54 stolen bases — but he has a bunch of important supporting cast members to rely on. Ketel Marte had just joined the organization the last time the Diamondbacks made the postseason and he’s one of the few pillars that has stuck around through the rebuild. He posted a 127 wRC+ this year, an improvement of 24 points over his down season last year. Walker posted one of the quietest 30 HR/100 RBI seasons you probably didn’t hear about, and Lourdes Gurriel Jr., Gabriel Moreno, and Geraldo Perdomo have all proven to be solid contributors at the plate.

With the Woodruff news dominating the narrative now, the Diamondbacks have an opportunity to continue their surprising season with a series win over the Brewers. Neither team seems likely to score all that many runs during this series; instead, it’ll all come down to which team is able to hold on to whatever tiny lead they can scrap together. The decision about when to use Freddy Peralta is something to watch for, though the series might just come down to which bullpen is better in the end.