I wrote this entire piece last week, only to have Mozilla unexpectedly crash and, even more surprisingly, not restore my session properly. Here's take two:
I am going to try to pick interesting cases: players who were injured, or had (seemingly) fluke productive or unproductive seasons. For outside forecasting, I'm including PECOTA, Marcels, ZiPS, Bill James, and CHONE forecasting systems, as well as a quick and dirty method of my own to attempt to project 2007 performance. Anyone reading this who has read me before would probably guess that my method uses batted-ball data, and you would be correct.
With an assist from Eric Simon of Mets Geek and Amazin' Avenue, I've got myself a nifty spreadsheet that corrects players' batting lines for the difference between their Batting Average on Balls in Play and their expected Batting Average on Balls in Play. The need for a spreadsheet comes in with the adjustment made to this; when you add in the difference to the batting lines, every extra or missing hit is counted as a single. Eric tweaked it so that the extra SLG points are distributed according to their hit-type rates, meaning a few extra points for extra-base hits. For many players there will not be any difference, but it will help to correct slugging percentage for a few players on either end of the extremes.
The projection systems no longer expect Blalock to be a star, although they do forecast that he will outperform both his 2005 and 2006 seasons--you can blame the weighting of his 2004 season, .276/.355/.500, for that. You also want to take note that the correction for batted-ball data gives him a line that looks a bit better than his actual one. Blalock's BABIP of .296 was .034 points under his expected BABIP, but that doesn't mean all of those lost points should have been hits. Blalock has been turning into more of a groundball hitter lately--another reason why his power has declined--and there's a good chance that not all of those points of BABIP were bad luck, and some just would have been ground outs.
Either way, Blalock is better than his 2006 campaign shows, but nowhere near the impact player his stat lines showed him to be during the 2003-2004 seasons. If Blalock performed like 2005 from here on out, I wouldn't be surprised.
Morgan hit .235/.396/.463 last year, and none of the projection systems envision much improvement on that for this coming season. The batted-ball correction gives him a slight boost in each category, which isn't that significant overall. The injury is the cause of Ensberg's demise; he hit .235 and still managed an ISO of .228, meaning his power is still there. Let's not forget his walk rates are incredible, and not just the product of a slowing bat. Ensberg's walk rates were high as the season began, and he did not hit the ball the opposite way more often, a sure sign of a slowing bat in a veteran.
I have no problem envisioning an Ensberg that reaches his 75th percentile PECOTA forecast in 2007, hitting .278/.390/.520.
In fact, let's take a look at something I wrote in my most recent Player Profile column over at Baseball Prospectus:
This also looks very similar to his high-end PECOTA forecasts; although his 75th percentile projection is just .275/.372/.493, his 90th is .293/.392/.537. If one is to believe that his walk rates from 2004 and 2006 are true indicators of his skill level, then a healthy Chavez should be able to wreak havoc on American League pitchers. Whether or not Chavez will be able to remain healthy for the entire year is a different story, and his high flyball rates worry me somewhat, as far as his maintaining a BABIP in line with his expected BABIP goes.