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Wednesday, November 08, 2017

How Bad Was Amed Rosario’s Debut, Exactly? | FanGraphs Baseball

Not exactly an optimistic view of Rosario’s future. Of course, it’s not exactly based on a lot of data.

Jim Furtado Posted: November 08, 2017 at 06:42 PM | 8 comment(s) Login to Bookmark
  Tags: amed rosario, mets

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   1. Never Give an Inge (Dave) Posted: November 08, 2017 at 09:03 PM (#5573289)
Reminds me a bit of when Rob Neyer called Jose Reyes the worst everyday player in baseball at a similar age. Not saying Rosario will be as good as Reyes, but I don't read that much into 170 PA at age 21.
   2. Walt Davis Posted: November 08, 2017 at 09:30 PM (#5573294)
What if he’s more Cristian Guzman or Orlando Arcia ...

Over the bulk of his career, Guzman put up 13.4 WAR, -4.4 WAA. That's not great but it's a perfectly solid player. A very good baserunner (apparently) but a bit below-average fielder, he'd have been average with an above-average glove.

Arcia is all of one year older than Rosario so we have no idea what he's going to be yet either. But for what it's worth, in his first full season at age 22, he put up 2.6 WAR, 0.8 WAA so I assume the Mets would be pretty happy if Rosario produces consistently at that level.

...than Xander Bogaerts or Alex Rodriguez?

One of these not remotely like the other, In a list that also features Peralta (31 career WAR) and Matt Williams (46), why would you single out Bogaerts as a top outcome? Bogaerts has been about 3-3.5 WAR while apparently playing poor defense.

Exit velocity and launch angle, on the other hand, are supposed to take only around 50 balls in play to stabilize.

I don't believe this for a second. It doesn't even make sense to talk about something as highly variable as launch angle stabilizing. It's primarily about "barrels" anyway and in 2017, even the very best (Judge) only had about one barrel per 8 PA so would have about 6 after 50. Rosario was down about 2% but "typical" seems to be maybe around 5% ... an area that includes some pretty good 2017 hitters like Cano, Rendon, Marwin, Beltre, Gennett ... and even the all-or-nothing Mark Reynolds. You can't come close to telling the difference between 2% and 5% in a sample of 50.

Furthermore, mean exit velocity doesn't appear to have a strong relationship to overall production ... I doubt mean launch angle does either ... and I'm reasonably confident that all they're picking up with mean launch angle is GB/FB/neutral hitter.

to the author's credit, he gets at this a bit in the histogram of Rosario's EVs vs. league EVs. Shift Rosario's distribution about 5 MPH to the right and you're starting to get something pretty similar.

The giant glaring flaw for Rosario is 3 BB and 48 K in 170 PA. It barely matters how hard he hits the ball or at what angle if he's going to K 30% of the time while walking 2%.

On the avg EV point, there's a neat cluster at 89.6:

Murphy 136 OPS+, 43 doubles, 23 HR, 3.7% barrels/PA
Hosmer 132 OPS+, 31, 25, 5.2%
Bellinger 142 OPS+, 26, 39, 7.5%
Moss 84 OPS+, 14, 22, 8.7%
Freeman 157 OPS+, 35, 28, 8.9%
Smoak 128 OPS+, 29, 38, 9.3%

So we've got OPS+ from 84 to 157 although all are good except Moss. Some guys are pounding out doubles, some are pounding out HRs. Barrels/PA varies from 3.7 to 9.3.

Now here they are for 2016, EV and OPS+

Smoak 91.4, 88
Freeman 91.2, 157
Moss 87.9, 106
Bellinger NA
Hosmer 91.7, 102
Murphy 90.7, 155

So Smoak and Hosmer saw their avgEV go down by 2 MPH and their OPS+ go up substantially. Freeman's went down 1.5 MPH and his production was the same. Murphy went down 1 MPH and down in OPS+ while Moss went up in EV but down in OPS+.

What happened? Well, unless batters actually hit the ball substantially LESS hard in 2017 than in 2016, the measurement has changed. I assume somebody noticed. Anyway, Freeman/Smoak were about 40th in 2016 at 91+ MPH but have only dropped to 51st at 89.6 ... in 2016, 89.6 would have put you around 125th. Alternatively, in 2017, Smoak's 91.4 from 2016 would have tied him for 10th.

Some statcast nerd will have to tell us what changed in how it's measured but it seems highly likely that it has. So don't put much value in drops in avg EV on the order of 1-2 MPH from 2016-17.

Still, regardless of the "true" change in EV, Moss went from a 106 to a 84 OPS+ while Smoak went from a 88 to a 128. There is presumably a reasonably strong connection among avgEV, avgLA, barrels/PA and on-contact production. And that is an important part of overall production but it's still contact rates and K/BB ratios that will largely determine how much value you'll produce with the bat. And with regard to Rosario, the EV, LA, etc. is tangential for a player with a 48/3 K/BB in 170 PA. The key question is how well he can control the strike zone then, conditional on our guesstimates of that, we can discuss the range of outcomes.

   3. Dog on the sidewalk Posted: November 08, 2017 at 10:03 PM (#5573297)
The pessimism expressed at the beginning and end doesn't seem to mesh with the rest of the article. And to piggyback on to what Walt said, not that I value that comps list much, but a list where A-Rod appears and Xander Bogaerts is 4/9 in value is not something that causes me to worry.

My expectations for Rosario weren't helped by his debut, but I wouldn't say it really hurt them, either.
   4. Howie Menckel Posted: November 08, 2017 at 11:19 PM (#5573307)
   5. Voodoo Posted: November 08, 2017 at 11:35 PM (#5573308)
Didn't Javy Baez have a historically awful debut, too? (not sure that this makes any difference in terms of long term outcome projections)
   6. Spahn Insane Posted: November 09, 2017 at 12:03 AM (#5573312)
Báez was actually a good bit worse than Rosario in his debut.

Báez, 2014: -1 WAR in only 52 games, 169/227/324, 95(!):15 K:W in 229 PAs, 52 OPS+
Rosario, 2017: .2 WAR in 46 games, 248/271/394, 48:3 K:W in 170 PAs, 73 OPS+

Both guys were 21. Now, Báez walked more (or, “less infrequently”) and had a little more power, so his getting the strikeouts back into a somewhat normal stratosphere (144 in 508 PAs, a massive improvement) led to a decent BA, and his being a thoroughly adequate bat this year. But Rosario showed decent power too (.146 ISO).

The walk rate is terrible, but I’d say it’s a little early to start hyperventilating about Rosario as a bust. I mean, even if he doesn’t improve much his floor is probably Shawon Dunston.

Edit: It still blows my mind that Báez didn’t debut until August 5, and still almost managed to strike out 100 times.
   7. Bring Me the Head of Alfredo Griffin (Vlad) Posted: November 09, 2017 at 10:49 AM (#5573433)
I don't think Rosario is ever going to walk much, but it's pretty normal for a guy's K rate to get a temporary bump up when he's promoted to the majors for the first time.

No reason to freak out about his future.
   8. The usual palaver and twaddle (Met Fan Charlie) Posted: November 09, 2017 at 11:18 AM (#5573475)

Reminds me a bit of when Rob Neyer called Jose Reyes the worst everyday player in baseball at a similar age. Not saying Rosario will be as good as Reyes, but I don't read that much into 170 PA at age 21.


I don't think Rosario is ever going to walk much, but it's pretty normal for a guy's K rate to get a temporary bump up when he's promoted to the majors for the first time.

No reason to freak out about his future.

I see Rosario as Reyes-lite right now. Looks exactly like an identical profile at this nascent stage of his career.

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