Projecting Amed Rosario

The Mets have called up uber-prospect Amed Rosario to take over at shortstop. Rosario his more than earned this opportunity through his performance in the minors. Despite spending just two months at Double-A, the Mets started Rosario at Triple-A this year, and he rose to the challenge by hitting .328/.367/.466.

Rosario’s offensive performance has been impressive, but it’s less impressive after accounting for his environment. He’s played in the hitter-friendly Pacific Coast League, with half of his games coming in the hitter-friendly Las Vegas ballpark. Still, his 16% strikeout rate coupled with his speed (19 steals, tied for third in the PCL) and propensity for hitting doubles and triples (his seven triples are tied for eighth in the PCL) is encouraging.

Rosario’s hitting isn’t what makes him a stud prospect, however. More impressive than his offensive numbers is that he’s produced them while playing shortstop as a 21-year-old. A shortstop does not need to hit all that much to be a useful big leaguer — the average shortstop has hit .257/.309/.402 (85 wRC+) this year — so any sign of offensive life from a shortstop prospect is encouraging. And since he’s only 21, there’s a very good chance that he will grow as a hitter as he matures.

My KATOH system pegs Rosario for 7.2 WAR over his first six seasons by the stats-only method, and 12.1 WAR by KATOH+, which incorporates his No. 4 prospect ranking from Baseball America. Those marks place him 40th and 10th, respectively, among prospects. Those point estimates don’t tell the whole story, however, as KATOH sees some serious star potential in Rosario, giving him a roughly 1-in-4 chance of racking up over 20 WAR over the next six years. For reference, Troy Tulowitzki was the only shortstop who crossed that threshold in the six-year span that ended in 2016.


To put some faces to Rosario’s statistical profile, let’s generate some statistical comps. I calculated a Mahalanobis distance between Rosario’s Triple-A performance and every season since 1991. In the table below, you’ll find the 10 most similar seasons, ranked from most to least similar. The WAR totals refer to each player’s first six seasons in the major leagues. Please note that the Mahalanobis analysis is separate from KATOH. KATOH relies on macro-level trends, rather than comps. The fates of a few statistically similar players shouldn’t be used to draw sweeping conclusions about a prospect’s future. For this reason, I recommend using a player’s KATOH forecast to assess his future potential. The comps give us some interesting names that sometimes feel spot-on, but they’re mostly just there for fun.

Amed Rosario Mahalanobis Comps
Rank Name KATOH+ Proj. WAR Actual WAR
1 Joaquin Arias 6.0 1.0
2 Hanley Ramirez 10.8 31.9
3 Juan Castro 6.7 0.1
4 Jimmy Rollins 8.6 19.1
5 D’Angelo Jimenez 13.2 7.4
6 Omar Infante 8.3 3.4
7 Alex Gonzalez 7.7 4.8
8 Erick Aybar 12.5 14.4
9 Royce Clayton 10.7 13.6
10 Asdrubal Cabrera 8.6 13.3
11 Alcides Escobar 9.3 10.4

Rosario can help the Mets in a lot of ways. He can hit; he runs well; he plays arguably the most premium defensive position; and most exciting of all, he’s a 21-year-old who should continue to improve. The one thing he doesn’t do right now is hit for power, but Eric Longenhagen has speculated that more power might be on the way. Eric gave Rosario a 55 raw power grade when he ranked him as the No. 3 prospect in baseball before the season. Mets fans and prospect enthusiasts have been eagerly awaiting Rosario’s arrival since he broke out at High-A last year. Now, he finally gets his chance.





Chris works in economic development by day, but spends most of his nights thinking about baseball. He writes for Pinstripe Pundits, FanGraphs and The Hardball Times. He's also on the twitter machine: @_chris_mitchell None of the views expressed in his articles reflect those of his daytime employer.

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southie
5 years ago

One of the more encouraging write ups for a prospect in recent memory. I expect league avg SS bat with plus defense this year for starters. More optimistic next season with bat. Fun times.