If you had to look at the whole of 2012 -- the excitment, the disappointment, all of the individual breakouts and meltdowns -- and wanted to take one thing away from it that would bear well for the future, I think that most Pirate fans would take Pedro Alvarez's breakout season. At this time last year, all of us were flat-out terrified of Pedro's future as a big league player: his trip through the minors was good but not quite as excellent as expected and his 2011 was so disastrous that it wasn't hard to imagine that he'd never be quite right as a big league player. When he got off to a terrible start in April, people were rightly discussing whether he was one of the biggest draft busts in recent memory.
Starting on April 21st, though, Alvarez began to silence the doubters. He had two hits against the Cardinals on that day, then homered in both ends of a double header four days later, and by May 3rd he'd homered five times in 11 games and his seasonal OPS was up to .912. His season was a bit of a roller coaster from that point on, but he ended the season with 30 home runs, 25 doubles, a .467 slugging percentage, and a wOBA/wRC+ of .335/112 (that is: slightly above average). These numbers are encouraging for a hitter that was so very lost 12 months ago and you can even finesse them a bit to be even more so. If you eliminate Alvarez's terrible start (that is, if you start counting on April 21st), he hit .255/.330/.479 with 28 homers and 25 doubles in 139 games. If you start counting from after his second bad slump (from May 5 to June 15 he hit .143/.228/.223 across 33 games, then broke out of it by going straight-up Galactus on the Cleveland Indians), Alvarez hit .274/.352/.518 with 22 homers in 94 games.
This is all well and good, but picking arbitrary end points and using them to prove things that you want to see happen is a great way to be disappointed. It's every bit as instructive to point out that Alvarez's strikeout rate for the entire season was 30.7%, that his strikeout rate from April 21st onwards was 29.7%, and that his strikeout rate from June 16th onwards was 29.6%. In short, that means that Pedro Alvarez is striking out a ton whether he's not or he's not hot, and when the only thing a hitter does consistently is strike out a ton there's plenty of reason for concern.
In the entire history of baseball, there have only been 33 individual seasons in which a player has struck out 180 times or more. As you might guess, the list is heavily populated by current players. Adam Dunn, Ryan Howard, and Mark Reynolds are all on it four times and Jim Thome is on it twice. Dunn, Howard, and Reynolds are pretty instructive for our conversation here, so let's talk about the three of them.
Most people likely think of Howard as a more consistent hitter than Dunn and of Dunn as a more consistent hitter than Reynolds, but Howard and Dunn have been fairly streaky themselves across the seasons. Howard watched his OPS+ go from 167 to 144 to 125 from 2006-2008, which is a pretty significant drop that people tend to gloss over because of his huge homer and RBI totals. Smack in the middle of Dunn's run of four 40-homer seasons is 2006, when he had an OPS+ of 114. Reynolds is a known roller coaster, going from OPS+ of 127 to 97 to 116 to 107 over the last four years. It's easy to spot where these down years come from, too. If we consider Howard's prime to be from 2006 to 2009, his worst year was 2008 and that was the year he had the lowest batting average (.251). In Dunn's four straight 40-homer years, he only hit .234. In Reynolds' best season (2009) he hit .280. In his worst (2010), he hit .198.
We don't need to go deep into all of this right now, but the generally accepted concept in sabermetrics right now is that hitters, to some extent, lose control over the outcome of any at-bat in which they put the ball in play. Since we're deriving norms from huge numbers of at-bats, any given season can be defined as a small sample size in which you can expect some amount of variability. In English, every once in a while a .300 hitter like Freddy Sanchez hits .344 and wins a batting title simply because the randomness of the universe allows for him to have a season where a ton of balls find gaps and holes that otherwise might not. Three true outcome hitters like Alvarez, Howard, Reynolds, and Dunn spend most of their time homering, striking out, or walking which means that the number of balls they put into the field every season is lower than most hitters, which in turns means that they should be even more prone to this variability (NB: I haven't actually researched whether high strikeout hitters have higher batting average variation than the average hitter and I'm sure that someone has, so if someone has and I'm wrong please let me know).
As it relates to Alvarez, this is all important because his strikeout rate, walk rate, and line drive rate didn't change much from 2011 to 2012 and while we can infer that he definitely hit the ball more solidly because his pop-up rate dropped and his HR/FB took a jump as a result, the differences there probably don't explain the dramatic improvement we all perceived for him last year. There are more concern points, too. Alvarez's strikeout rate is above 30%, while the two hitters from this group that had long stretches as good hitters (Howard and Dunn) are below 30%, while Reynods is above 30%. Alvarez also has the lowest walk rate of the group and he's the only one that's below 10%. The reason that Dunn managed to sustain an OPS+ of 136 between 2004 and 2010 despite a .254 batting average and a aircraft carrier full of strikeouts is because he walked 16.2% of the time (750 bases on balls in 4634 plate appearances). Alvarez drew 57 walks in 586 plate appearances -- 9.7%. To be a really good hitter, Alvarez needs to walk more than that if he's going to strikeout as much as he does.
I'm not mentioning this to be depressing, just to point out that Alvarez is still very much a work in progress despite all of the home runs last year. The reality is that he's still two weeks away from his 26th birthday, that he's only got the equivalent of two seasons worth of Major League experience, and he's only played one full big league season from beginning to end. I'm saying that there's room for improvement, but he's still at a point where it's not unreasonable to expect improvement from him. The reality, though, is that I'm still incredibly unsure of what he's going to do in 2013.