Amed Rosario is improving at the plate

I remember being so excited when Amed Rosario was going to make his major league debut. A 21-year-old shortstop who projects to be a superstar making it to the majors with high expectations is not the kind of exciting occurrence to which Mets’ fans are accustomed to...instead, we’re used to soul crushing disappointment.

The Mets had no chance of making the playoffs when Rosario made his debut on August 1, 2017, but it was time for the young prospect to make his hit the bigs. He was hitting .328/.367/.466 in Triple-A Las Vegas, and even when factoring in how hitter friendly the Pacific Coast League is, that was still an impressive line from a 21-year-old shortstop. Clearly he had nothing left to learn there, and holding him down would only impede his development.

Prospect analysts loved almost everything about Rosario. They believed he had the ceiling of a 70-grade hitter who could grow into above-average power. Despite his size, his athleticism should allow him to play average to above-average defense at shortstop, and he has a plus arm. That athleticism also means that he should be able to provide value on the basepaths. A prospect writer I once spoke to about Mets’ prospects described Rosario as “Derek Jeter with plus defense.” I understood what he was trying to say, but rest assured that I rolled my eyes at that description.

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Well, two years in, and none of that came to pass until recently.

Rosario’s 46-game debut in 2017 was pretty disappointing, though perhaps it was not too bad considering his age. He hit only .248/.271/.394 while striking out a lot and never walking. That may sound like hyperbole, but he walked only three times in 170 PA, a Dee Gordon-like 1.8 percent rate, and he swung at pitches at a Javier Báez-like rate. In fact, his 48 percent O-Swing rate is nearly five percentage points higher than Javy’s career rate!

Thankfully, Rosario’s plate discipline and contact skills improved the following year to rates more in line of what was expected of him. His offense improved slightly to .256/.295/.381. An eight-point improvement in wOBA is not much, but it is not insignificant either.

The most baffling Rosario struggled was in the field. Scouting is really hard, of course, but one of the easier things to get right is defense. DRS thought that he was Jeter-bad at shortstop at -16 runs. Personally, I just didn’t see it. That being said, he definitely did not look good defensively. His footwork was often awkward and he made mistakes he should not have been making on routine plays. I think his defense was closer to his -5.2 UZR and -6.6 FRAA than the terrible DRS numbers.

On the bright side, Rosario’s baserunning was quite good! While he did get caught 11 times in 35 attempts, he ran the bases very well outside of that. Overall, he was worth 1.5 fWAR for the year, which is not too bad for a 22-year-old in his first full season.

The 2019 season looked like more of the same for Rosario through June. He was hitting .255/.293/.414, and even though he was hitting for significantly more power with nine home runs, it was tough to to discern if that was him or the juiced balls. His defense did not look any better by the advanced metrics or the eye test, and even his baserunning took a hit as he is leading the league with 11 times caught stealing. Yes, he is still young, but it was not unreasonable to start wondering if Rosario’s development had stalled.

Thankfully, that might not be the case. In 188 PA since the beginning of July, Rosario has been raking, hitting .350/.388/.497, good for a 136 wRC+, and his strikeout rate has dipped below 15 percent. However, he still is not walking much, and that batting line is inflated by a .404 BABIP. He also has not been facing strong competition. Still, a .373 wOBA that is 70 points higher than his career rate is tough to explain away via luck, even in fewer than 200 PA. Rosario is legitimately hitting the ball harder, though, with about a 35 percent hard-hit rate compared to a 29 percent rate, per FanGraphs.

One of the keys to his recent success appears to be simply making more contact. A guy with his bat speed can do great things if he is able to make regular contact. He is swinging at balls in the zone just as often as ever, but now he is making contact a whopping 94.4 percent of the time on those pitches. Unfortunately, he is not making any more contact on pitches outside the zone that he swings at far too often. If Rosario could reduce his O-Swing rate to even just league-average rates, he could be come a special player. He really could.

It is still early, but it is great to see Rosario’s bat improving, and hopefully he will continue to do so. It is exactly what the Mets need now that they are back in the playoff race. The defense still needs a lot of work, though. Maybe the Mets can lure Ron Washington away from the Braves?