We all thought he'd return to his norm, which is pretty much what he did or was in the process of doing when the season ended.
A hot player (or lucky player) is likely to return to his norm just like a guy in a slump.
That doesn't mean a player's "norm" can't change, trend or evolve... most do over their careers, and that's where most predictions rely on age or experience curves to adjust a player's projection based on what has happened to similar players at certain points of their career. It's not an exact science as Papi showed, and sometimes outside influences occur as Barry Bonds showed us.
Sandy Leon's career minor league OPS is .654. Within his farm context one notices some horrendous bad stretches and seasons and a couple very high spikes (.856 in 2012 and .938 in winter ball of 2013). His OPS in limited scattered PAs with WSH was .533. It was .439 last year in 128 PAs for the Sox. So, after going through an incredible hot streak (not unprecedented in his professional career), what happened?
A .539 OPS in September. That's pretty close to what his career ML OPS was before the hot/lucky streak- whichever you want to call it. Now, the issue is this, because of that hot streak, his career ML OPS has risen from the low .500's to .681. His sample size is still very small at 518 PAs scattered over 5 ML seasons with countless demotions and promotions to and from the farm. What can we expect going forward? For those of you who feel what you were doing most recently counts more, what were you saying last July or August? How far back do you go? Some arbitrary number? If you count just Sandy's last month, you might project a Leon that falls in line with his previous ML OPS and his minor league OPS -between .530 and .630 maybe-- so .580ish? If you like to use a players last 3 months (223 PAs)- you'd think .755 is what we can expect. If you like to use his last season, then .845 might be your number, unless you factor in his .655 at AAA last year in 130 PAs (maybe .775?).
To me, I'll stick with projecting somewhere between his career MLB OPS of .681 and his minor league OPS of .654 knowing full well he could have a season much nearer .535 than .845, because that is where most of his career has been.
There really was an exact date Leon fell off a cliff-- August 26th. His OPS dropped pretty continuously from the start, but he still was "hitting over his head" for several months:
June 1.243
July .956
Aug. .893
Sept .539
He was still over a 1.000 OPS on Aug 26th. Who here could have predicted the correct date for his return to norm? He went 5 for 28 to end August (just 1 double and 1 BB). His September was not below his norm to "compensate" for his hot or lucky streak. It was almost exactly at his norm.
Perhaps Leon is a poor example, since his "norm" is not really established, but I used him as an example in response to this post.