Fernando Tatis Jr. is now an outfielder for the San Diego Padres. Despite his recent stint on the injured list — his third of the season, and his second related to his shoulder — he might end up collecting the NL MVP provided he can stay productive and healthy, all while moving away from the only position he’s played in professional baseball. In his return to action on Sunday, he raised his wRC+ to 172 and got his first playing time in right field. There wasn’t much to be gleaned from the four balls hit his way, however, leaving us to wonder how well he’ll handle the position going forward. Mike Petriello at MLB.com has covered the unprecedented nature of this move, but I want to take a look at what we can actually expect from Tatis defensively. I’m not the first to consider the question. Last week, Michael Ajeto highlighted Tatis’ defensive ability in an article for Baseball Prospectus and delved into the analytical precedent for shortstops who have recently made the conversion to the outfield. Today, I’ll look at what we might predict about Tatis’ outfield defense given some of the other data we have about his speed.
But let’s set the stage. The biggest flaw in Tatis’ game since his debut has been his defense. After a 2019 characterized by 18 errors and poor defensive metrics, he seemed right the ship last season. But his defense has since regressed, and while his -4.3 Def runs at shortstop this year hasn’t made him unplayable at the position, it’s certainly not ideal. Still, this move wasn’t necessitated by his play at short, but rather by Tatis’ recurrent shoulder problems and the Padres’ stated desire to shield him from further injury, though as Ajeto noted in his piece, whether that will actually work is an open question.
That’s how we ended up with Tatis in the outfield. Before getting too far ahead of ourselves, however, it’s important to know how his numbers at short are derived. His penchant for throwing errors is well documented and they do serve to drop his DRS, UZR, and Outs Above Average (OAA) considerably. We can peek at the component parts of UZR to separate the errors from Tatis’ range, but we aren’t even close to a three-year sample and thinking about UZR sample size is a Pandora’s Box that should be kept closed for today, anyhow. For our purposes, we’re not going to pay much attention to throwing errors or even Tatis’ range on grounders as a shortstop. The baseline we care about is how well he can play right field and quick twitch and speed are the parts of the shortstop skillset that seem mostly likely to translate to the outfield grass. Read the rest of this entry »