After a slow first two weeks to start the season (in which Rosario slashed just .186/.239/.209), he's been a necessary lineup fixture for Minnesota. Despite being consistently tied to a high likelihood of chasing pitches and flailing outside of the zone, he's seemingly been intent upon abandoning those descriptors and has turned over a new leaf. From April 18 until July 17, Rosario owns a .307/.341/.508 slash line. While he's still struck out significantly more than he's walked (51/13), the ratio has turned for the better on both sides.
Over the three years he's spent in the big leagues, the drastic strides at the plate this season are showing themselves numerically. Owning a 24.9% and 25.7% strikeout rate the past two seasons, he's cut the number to just 19.5% in 2017. He's struck out less because of having gone from a 14.5% swinging strike rate in 2015 (and 15.3% last year), to 12.6% this season. Swinging at less pitches out of the zone (38% in 2017 as opposed to 45.6% in 2015) is no doubt going to raise the water level as well.
During his debut season, only the Red Sox Pablo Sandoval (47.8%) and the Orioles Adam Jones (46.5%) chased pitches out of the zone more often than Rosario's 45.6%. Swinging through 14.5% of pitches he took a hack at, Rosario also fared 10th worst in baseball among hitters in 2015. Thanks to his increased discipline, he now ranks 17th lowest in baseball when it comes to chase rate (bad, but much improved), as well as 41st in SwStr% (which is a big leap). As witnessed by his swings and misses outside of the zone since 2015 as well, pitch recognition is something he's vastly improved upon.
While Rosario is far from an elite hitter at this point, it's no coincidence that his slight changes have helped to post his first big league OPS above .300. As things stand currently, he also paces the Twins with a .289 average. Still a work in progress, enough can't be made about the strides Rosario has made at the plate for Minnesota.
Unfortunately, the downside to the offensive growth is the defensive slide. After tallying a ridiculous 12 assists from left field to go along with 10 defensive runs saved, he's fallen off. In 2016, his big league efforts resulted in basically a league average fielder, and this season, he's been worth -7 DRS and -2.2 UZR. Although Twins fans have dealt with the likes of Robbie Grossman, Josh Willingham, and Delmon Young in left field, Rosario hasn't been any sort of steadying presence this campaign either.
There can't be enough noise made about how important Rosario's offensive changes have been. As the defense now holds him back, the wonder continues to be whether he can put it all together. Rosario at his best presents a dream outfield scenario for the Twins, but he'll need to present the reassurance that he's still capable of that. It's pretty crazy to think that we'd reach a point of Rosario being fine offensively while lacking in the outfield, but here we are. Minnesota needs him to come full circle, and doing so soon would be a nice boost.
