Josh Donaldson’s defense is a huge upgrade for the Twins

Heading into the off season, there weren’t many Twins fans concerned with upgrading the lineup. Returning nearly every impact bat from the 2019 Bomba Squad while losing four starters to free agency, starting pitching was on everyone’s mind. And while the Twins struck out on getting an impact starter in free agency, they did improve their run prevention by signing one of the best players on the market, star third baseman Josh Donaldson.

Defense is hard to judge on a statistical level. Some analysis is completed with DRS (Defensive Runs Saved), while others prefer to use UZR (Ultimate Zone Rating). And then there are the new metrics released recently by Statcast, specifically Infield OAA (Outs Above Average). Whichever metric you prefer, it is clear that Josh Donaldson’s defense will be a significant upgrade over Miguel Sano at the hot corner. But just how significant will that upgrade be?

Let’s start with Defensive Runs Saved. Over 8 seasons and 8,000+ innings at third base, Donaldson has been accountable for 68 runs saved, including a +15 mark in the category last year. Meanwhile, Sano has been worth -19 runs saved (or runs lost, in this case) at third base in just over 2,400 innings in his career, with a -5 mark in 2019 at the position. Donaldson’s +15 DRS ranked tied for 10th in all of Major League Baseball last season.

In four out of the five seasons Donalson has posted over 1,000 innings at third base, he also produced over +10 runs saved at the position. Conversely, Sano has been -5 or below the last three seasons, even while playing 793 innings or fewer in each of those seasons at third. Based on those numbers, a full season of Donaldson at third versus a full season of Sano at the hot corner is likely to provide a difference of around 20 Defensive Runs Saved for the Twins, even with some possible regression for Donaldson.

So what does 20 runs mean to the Twins? Think about it in the context of recent acquired Twins starter Homer Bailey. The journeyman starter gave up 83 earned runs last season in 163.1 innings pitched for a 4.57 ERA. If he were to give up 20 fewer runs last season, he would have sported an ERA of 3.48, something Twins fans would likely be a lot more excited about. Granted, Donaldson’s defensive value will be spread out over around 150 games, but the impact of saving 20 runs throughout the season is significant for the pitching/defense side of the equation for the Twins in 2020.

UZR (Ultimate Zone Rating) still has Donaldson as a plus defender, but wasn’t quite as bullish on his defensive skills in 2019. Generally a more conservative metric, Donaldson’s UZR of 2.4 was still ninth among all qualified third baseman, while Sano’s -6.7 UZR mark was 155th among all third baseman (out of 158, as he wasn’t qualified at the position). Donaldson has had a positive UZR in each season at third base (including a few as a top five third baseman,) but the metric doesn’t love his defense quite as much. Since Donaldson’s 2015 MVP season, the range factor (one of four factors that make up the metric of UZR) for Donaldson has dropped each year, including a negative mark in 2019. To see Fangraphs full explanation of UZR, look here.

As expected, Sano has posted negative UZR values every season, though his worst was certainly in 2019. UZR actually had Sano’s range factor listed near league average last season, though his propensity for errors really decreased his value in the metric’s eyes. Sano’s UZR per 150 games would have come out to a mark of -19.9, which would have easily been the worst mark in the majors (lowest: Jacoby Jones, -12.5). So while UZR doesn’t make Donaldson’s defense look quite as good, its reflections on Sano’s defense show a similar difference in the defensive upgrade that Donaldson provides over Sano at the hot corner.

Statcast’s new Infield Outs Above Average looks at defensive value a little bit differently, but paints a similar picture. Donaldson’s +8 Outs Above Average was third among all third baseman last season, while Sano’s -3 mark was 29th out of 35 among players that had at least 100 attempts at the position in 2019. While this metric may make it harder to quantify the value of the disparity, the range of players between Donaldson and Sano show the defensive improvement that the Twins will likely be making at the position in 2020.

The Statcast system also exhibits a player’s propensity to make plays in certain directions. Ranging towards shortstop in 2019, Donaldson was a +3 Outs Above Average, which could impact Twins shortstop Jorge Polanco. With more range at third base, the Twins could shift Polanco slightly more up the middle, possibility limiting his mistakes as well those of 2B Luis Arraez.

Adding a 5+ WAR player to the Twins lineup shows clear benefits on the offensive side. And while the eye test may say that Josh Donaldson is better defensive third baseman than Miguel Sano, the metrics also back up that statement in a big way. Even with some age regression from Donaldson in 2019, his past defensive numbers indicate that he will provide 15-20 runs of defensive value for the Twins in 2020 in comparison to Sano.

However, Sano will still be an everyday starter in the field at first base, but the other corner of the infield should be easier for the slugger to manage. Newly inked to a three-year deal with a team option, Sano will likely spend most of his time in that deal as the Twins’ first baseman. Having played just 223 innings at first base so far in his career, it is tough to judge how he will perform at this position, but the metrics on his past time there have him slightly below average as a first baseman.

While adding Josh Donaldson does not solve the Twins pitching problems, it may be a bigger boost to preventing runs than more people would imagine. If the having Donaldson at third does indeed save the Twins near 20 runs during the season, his defense alone could be worth a handful of wins to the team.