Ask Katrina And The Waves and they'll tell you that you can be walking on sunshine one year only to toil in obscurity thereafter. Without looking it up, can you name another Katrina And The Waves song? It's great to be a "one-hit wonder" if you're a starting pitcher, not so much if you're a band. You would think, "Geez, if they could write a hit song once, they must be able to do it again..." Give it a year. 2 years...10 years...Nope, not happening. Weird.
The same is true of baseball players. As tempting as it is to say, "But he hit 32 HRs in 2012..." or "The guy had a .393 OBP over an entire season..." the notion that a player must have it in them to repeat their success is as faulty as it is seductive.
The case of Ryan Sweeney was probably more straight-forward than the cases of Reddick and Barton. Sweeney put up a high WAR on the strength of some gaudy fielding numbers. UZR and its cousins are notorious for being overly volatile over a single-season sample and likely took an excellent RFer and mistook Sweeney for an out-of-this-world one. Combine this with a season in which his fair share of bleeders found holes and you have a season worth appreciating but not likely to be repeated.
What about Barton, and the hope that he will simply do again what he proved he could once? The fact is, things are never the same again. They can be better, worse, or just different -- but they are never the same. Barton will never again be 24 years old. He will never again be relatively unknown to the league's pitchers. He will never again be "pre labrum surgery".
What I think happened to Barton is a confluence of factors. Mostly, I think he is exceptionally good at recognizing changeups and breaking pitches that most hitters will chase out of the strike zone. Sometimes a high walk rate is thought to be the result of patience and a willingness to work deeper counts. That is certainly part of it, but the ability to draw walks is also largely a function of pitch recognition: The ability to recognize, and lay off, "balls that come in looking like strikes". Barton's skill in this area is exceptional and helped him to put up an exceptional .393 OBP in 2010.
However, at some point pitchers realized that they didn't need to fool Barton and could instead challenge him with fastballs, especially away, as a primary way to pitch him. Once pitchers started forcing Barton to put the ball in play, they neutralized his most elite skill.
Concurrently, Barton suffered a labrum injury that sapped his swing. He is now back at "100%". I put 100% in quotes because anyone who has ever been injured (if that's not you, what's your secret?) knows that some injuries get back to "it's like you were never injured" while in other cases you're just never quite the same.
Whether the labrum is part of the issue is anybody's guess, but at this level of competition being "back to 96% strength," in combination with being pitched away from your best skill, is enough to turn great success into failure. Regardless of what a player could do when he was 4 years younger, 4 years less known, and with 4 years less wear on the treads.
It's really not that uncommon for a player to have one really good season and then never to be able to replicate it again. There are just too many factors that change the landscape every 365 days. At this time 2 years ago, sure, Josh Reddick was walking on sunshine, but does that mean he can keep producing hits now?
Post Script following Saturday's game...If nothing else, at least Josh Reddick has now shown he can have "one great game"!