Like many of the rest of you, I'm excited to the point of giddy about Petey's recent hot streak. Also, like many of the rest of you, I'm a little worried about his ability to sustain a high level of production. Tim Williams over at Pirates Prospects wrote this piece about the different kinds of pitches Alvarez is seeing, while several people here have expanded on that. Suffering Buc has pointed to his BaBIP being absurdly low as a sign that he still has some good things in store this year. My concern was whether or not he could maintain high levels of production amidst all the strikeouts.
I first looked at his MiLB numbers. I included the span that he was sent down last year, and lumped together all levels in a given year to get more of a snapshot of the season.
2009: 465 AB's, 129 K's (27.7%), 71 BB (1.82:1 K/BB), .914 OPS
2010: 242 AB's, 68 K's (28.1%), 32 BB (2.13:1 K/BB), .896 OPS
2011: 142 AB's, 47 K's (33.1%), 25 BB (1.88:1 K/BB), .787 OPS
Alvarez maintains a K-rate in the high 20's, while still mainting ~2:1 K/BB rate and a high OPS throughout the minors (even in 2011, where he was "working on his swing" and rehabbing at times).
I have 3 years of MLB numbers to look at.
2010: 347 AB's, 119 K's (34.3%), 37 BB (3.22:1 K/BB), .788 OPS
2011: 235 AB's, 80 K's (34.0%), 24 BB (3.33:1 K/BB), .561 OPS
2012: 59 AB's, 23 K's (39.0%, 3 BB (7.67:1 K/BB), .767 OPS
Even in his "breakout" rookie season of 2010, Pedro still has an insanely high K-rate. The walk rate lowers dramatically from his MiLB numbers. As gorillagogo pointed out, Pedro had 12 K's in his first 19 PA's vs. only 11 in 43 PA's since then. Whether that's a function of the hot streak or just his averages normalizing, I can't say.
I went back and brough up his numbers at Vanderbilt, too.
2006: 240 AB's, 64 K's (26.7%), 57 BB (1.12:1 K/BB), 1.131 OPS
2007: 272 AB's, 65 K's (23.9%), 40 BB (1.63:1 K/BB), 1.147 OPS
2008: 167 AB's, 28 K's (16.8%), 28 BB (1:1 K/BB), 1.017 OPS
Alvarez's K-rate declined in each of his season at Vandy and was incredibly low his last season (though he only played in about 2/3 of the season after breaking his hand and missing 23 games). His K/BB was a neat 1:1, though his OPS dropped considerably.
I considered looking into his Team USA numbers (especially since he gets praise as a leader of the 2006 team), but I deemed both the sample size too small and the level of competition too varied to derive anything from them.
All in all, it seems that Pedro Alvarez has been a productive hitter, despite his high K-rate. This number has ramped up pretty significantly in MLB (and the walk rate has decreased similarly), but his rookie season was considered somewhat of a success. I see no reason why he can't duplicate those numbers and be a regular contributor. Like everyone else, I'd LOVE to see Petey develop into the 5+ WAR/year slugger we thought he was going to be coming out of Vandy... but I'm happy to settle for a productive MLB 3B who strikes out a ton but produces a decent amount of power somewhere near the middle of the order.