I've been seeing a lot of talk about bringing up Duvall because of his hot hitting. Here's where sabermetrics comes to the rescue, from the hype.
ogc thoughts
First off, I have to state that I have nothing against Adam Duvall. I like him as a prospect, particularly his power, but he needs to prove that he can field a position as well as just hit in the majors. Like any fan, I would love for a guy to come up and do what he's doing in AAA right now, hitting .431/.455/.824/1.278 with 4 homers in 51 AB (13 AB/HR) and 15 RBI in 12 games. Sign me up!
But, unfortunately, AAA is not the majors and he's only had 51 AB. SSS to the extreme, it is two weeks worth of games, a drop in the storm. And remember, the vast majority of pitchers in AAA are not good enough to pitch in the majors, lacking a major out pitch, for the most part.
Nobody is mentioning his 15 K's in those 51 AB. This is a miserable 70.6% contact rate. Which would only get worse in the majors, where most of the major league pitchers have out pitches that enable them to stay there and not end up in AAA.
Nobody is mentioning his .545 BABIP, which nobody in MLB history has ever duplicated in a season. Even the best hitters of our era, like Ichiro, never maintain an BABIP that high over a full season. He did reach .399 (again, he was one of the best of this era) in 2004, and .389 another season, but his career BABIP is .343 and over his best period of years, .357, which are considered great for a hitter. And he was one of the fastest players around, which helped him beat out grounders for infield hits.
Duvall is not much of a runner, so he's not going to get many of these. So what are the odds of him having a .545 BABIP in the majors? Especially in light of his sad 70.6% contact rate. Which might be fine if he was walking a lot, but with only 3 walks in 55 PA, he isn't much of a walker either. Which is another sign that he's not that great a hitter (because good hitters generally walk a lot, while doing other good things with his bat), and therefore unlikely to be able to maintain such a high BABIP.
Even his career numbers for BABIP are not as good as that. Individual hitters attain their own levels of BABIP. And remember, these were achieved in the minors, there will be a reduced ability to achieve these numbers in the majors, what sabers call Minor League Equivalencies. Each has their own methodology, but essentially the idea is that the competition is that much tougher in the majors, and thus, say, an 1.000 OPS guy in AA, might be a .800 OPS in AAA, and a .600 OPS in majors (my own made up numbers to illustrate how the process might work) I'm not sure what the exact translations are, but I would note that I noticed that guys who hit 1.000 OPS in AA is a sign of a guy who will get chances in the majors: Sandoval, Bowker, Ishikawa (but against RHP), Schierholtz, Belt are ones who come immediately to mind, so you can see the checkered history of that (and again, they hit over 1.000 OPS in AA!).
Some are able to learn at each level and advance, like Duffy or Panik, but the vast majority of players who hit very well in AA do not necessary make it in the majors. There is a severe weeding process and many a prospect (Linden, Feliz, Ishikawa, Bowker) come up from AAA after killing the ball there, and not do all that well. Swing and miss guys like Duvall usually just end up missing even more in the majors. If he could get his contact rate up into the 85% rate, I would have greater hope for him.
And I wish him all the best, as I do all Giants prospects. But calling him up now is just an act of desperation, a hope to catch lightening in a bottle. Just because Duvall has been very very lucky thus far in just a couple weeks of games does not mean that he's going to duplicate that at the major league level, particularly given his lack of overall contact, his high BABIP and low walk rate.
He will need to continue to hit like this into June before I would start to take notice and think that this might be real, it is not impossible to strike out so much and still do well in the majors, but two weeks is not enough for me to believe. If I were totally tied to statistics, the amount of time statistically necessary to verify him would be too much time to take, probably a couple of season's worth, and that's obviously too long a time. I don't think that you can wait for confirmation in baseball or you will never make any moves at all until the guys career is over.
Stats help point out stuff, but then intuition and guts (i.e. scouting) need to be part of the overall equation. I don't have the scouting, so two months seems fair to me, he would have earned a chance with such hot hitting over an extended period. But everybody is different, I recognize that. Still, two weeks is just too short, statistically just too short.