In September 2008, a journeyman utility player of whom most baseball fans had never heard was starting to see some regular playing time. He was a player whose usefulness was more or less based entirely on his defensive versatility. But as the season wound down, he suddenly started hitting the tar out of the ball. Had you checked the monthly league leaders for whatever your preferred power statistic is—say, slugging percentage (.732) or ISO (.411)—you'd have been shocked to see him up there with the most prolific sluggers in the game.
His name was Ben Zobrist, and by some metrics he was the most valuable player in baseball the next season.
Another unspectacular veteran soon followed in his footsteps. The next September, a virtually unknown player showed up on the slugging leaderboards, but he was hitting the ball out of the park with even greater zeal than Zobrist had—witness his 11 home runs in 29 games. You might not have known him then, but surely you've heard of him now. His name is Jose Bautista.
You can draw a number of attenuated connections between Zobrist before his breakout 2009 and Bautista's coming out party in 2010—and two years ago I did, following that trend to predict that Mike Morse would be baseball's biggest breakout hitter in 2011. So I am now fully and unwaveringly convinced that this pattern will hold up in perpetuity. (My model's failure last year was just the exception that proves the rule.)
The original story I had constructed for this infallible system was overly complicated, but essentially it boils down to this: When a player who has no business placing among the best power hitters in baseball places among the best power hitters in baseball at the end of a season, he will be among the best power hitters in baseball next year. And three of the last four years it's held true.
Facetiousness aside, I think this idea has some real logic supporting it. One month is far too small a sample size to draw any firm conclusions, but a few weeks is long enough for it to be at least interesting when a player with no history of hitting the ball hard ranks up there with names like Giancarlo Stanton and Miguel Cabrera. And if that September outburst coincides with a mechanical adjustment or a new approach at the plate, it stands to reason that the power surge would carry over into the next season.
But forget whether it makes sense—this system is foolproof. (Except, of course, for someone who shall not be named hitting .177 last year.) And so, I can say with absolute certainty that the biggest breakout player in baseball this year will be: Jason Castro.
For those who weren't paying close attention to Houston baseball last September (don't worry, you weren't alone), the 25-year-old catcher happened into some serious power in the season's final month. He hit four home runs in 60 plate appearances after September 1 (compared to the same number in 452 career PA through August 31). He slugged .500 (career average on August 31: .333), posted a .269 ISO (.093), and reached an eye-popping 1.167 power factor (.394).
Perhaps most jarringly, it took just 13 fly balls for Castro to collect his four late-season home runs; until September 2012, just four of the 103 MLB flies he'd hit left the yard. Thirteen batted balls is a tiny sample, but consider that only five hitters with at least 50 September plate appearances beat Castro's 31 percent HR/FB rate: Mike Napoli, Giancarlo Stanton, Chris Davis, Michael Morse, and Miguel Cabrera. Those are five of the most powerful sluggers in baseball, and I for one wouldn't have expected Castro to place among their ranks.
Nor is this just a case of Castro reaching his potential. His minor-league résumé is impressive (it's not easy to make Baseball America's Top 100 Prospects list twice), but even at the lower levels he wasn't known for his power. Before September he hadn't slugged .400 or notched an ISO over .100 since his days in High-A. Perhaps some optimistic scouts saw this potential in Castro, but he had never demonstrated anything close to this kind of pop in his professional career.
Admittedly, Castro isn't the perfect fit for this model. Even in a system based entirely on reading too much into small sample sizes, four home runs isn't much. More importantly, Castro is only 25 years old and is already seen as a very talented player. A power surge from a still-maturing former top prospect is hardly the same as it would be from a veteran journeyman who had seemingly plateaued somewhere around replacement level; in that sense, Castro doesn't fit the profile nearly as well as, say, Chris Denorfia. But the greater point—that Castro had no business ranking towards the top of the power leaderboards yet he did—still remains.
So there you have it: guaranteed proof that Jason Castro will be the 2013 breakout player of the year. You're welcome.