Yesterday, we looked at the teams that improved the most defensively from 2019 to 2020.

I would describe most of the teams that declined defensively as doing so marginally. Very few big-ticket acquisitions were of below-average defensive players (Nick Castellanos to the Reds being the biggest exception). So that leaves us with just a few teams that might see a drop-off.

Let’s look at the teams that we expect to decline the most.

The Decliners

Brewers

When the Brewers let Yasmani Grandal go in free agency, they went for offense rather than defense in finding his replacement, Omar Narváez.  Narváez had an OPS + of 119 and 120 the last two seasons and should fit well into the Brewers lineup.

But they’re going to have to figure out what to do about his defense. He’s cost his teams 32 runs with his catching defense last season, the worst Runs Saved for a catcher in the majors. Narváez struggles with pitch-framing (he sometimes takes pitches out of the strike zone with the way he catches them) and pitch blocking, which means that backup Manny Piña will likely see a lot of end-game time.

The Brewers also have a new regular first baseman, with Justin Smoak replacing Eric Thames (who is now with the Nationals). Thames saved two runs there last season. Smoak cost the Blue Jays seven in about a half-season, the fourth straight year he’s posted a negative Defensive Runs Saved.

Also with the Brewers, keep in mind that Keston Hiura is likely to play every day in his second season. Hiura can hit but showed last season that he had work to do on the defensive end. He had -5 Runs Saved in 81 games.

Red Sox

With the Red Sox, one player’s departure could make a big difference.

Mookie Betts averaged 23 Runs Saved in right field the last four seasons, though he totaled “only” 17 and 16 the last two seasons (in which he averaged 126 games). His likely replacements are Kevin Pillar and Alex Verdugo, the latter of whom had a back injury last season.

Pillar put up Betts-like numbers in center from 2015 to 2017, but those dipped the last two seasons. He took alright to right field with the Giants (two Runs Saved in a small 27-game sample), but he’s likely going to be unable to replicate what Betts did. If Verdugo is healthy and plays as well in the outfield as he did last season (combined 14 Runs Saved) the drop-off might not be as bad.

Diamondbacks

Let’s qualify this by saying that the Diamondbacks are working from a position of great strength given that they’ve ranked first and second in the majors in Runs Saved the last two seasons. But their outfield may take a hit this year with the departure of Dyson and the acquisitions of Marte and Kole Calhoun.

Both Marte and Calhoun have good histories in the outfield, but their most recent performance at the positions they’re expected to play aren’t great. As noted in the Pirates section, Marte hasn’t handled center field like he handled left. He cost the Pirates nine runs there last season.

Calhoun dropped from seven Runs Saved in 2018 to -1 in 2019. He may have been hurt by positioning.

Per Baseball Savant, Calhoun played 13 feet shallower in his home park in 2019 as he did in 2018. That may explain why his numbers were excellent on shallow fly balls, but poor on deep ones (more likely to be doubles and triples). Keep an eye on how the Diamondbacks position Calhoun. If they figure that out, it may negate the issues he had last season.

Giants

The Giants have some early issues with two of their top defensive players, first baseman Brandon Belt and third baseman Evan Longoria, injured. But this is more about catcher where Buster Posey’s departure looms large. Posey saved 14 runs at catcher last season and has saved at least 10 runs in four of the last five seasons.

The Giants’ catching situation is a massive unknown right now, with Rob Brantly, Tyler Heineman and Chadwick Tromp the likely placeholders until the team deems top prospect Joey Bart ready to go. But we do feel pretty safe in saying that none are likely to be as good as Posey is (Brantly has rated well below-average in the past) and none of them are likely to be close to his level.