Austin Jackson's Historic Improvement

Center fielder Austin Jackson has gone through a remarkable transformation in the first half of 2012.  The Tigers lead-off hitter has improved by leaps and bounds over 2011 on just about every statistical measure.  He has raised is batting average from .249 to .323, his on-base percentage from .317 to .405 and his slugging percentage from .374 to .538.

Looking at Jackson's overall production, his Weighted On Base Average (explained here) has increased from .309 in 2011 to .400 in 2012, a 29% change over 2011.  If we use OPS instead, AJax has improved by an extraordinary 37% (.691 versus .943).

I wanted to see how Jackson's jump in OPS would rank among past hitters.  So, I looked into my database (provided by Baseball-Databank.org) to determine the biggest one year increases since 1901.  I limited my analysis to hitters with at least 400 plate appearances for the same team in two consecutive seasons.  Table 1 below shows that if Jackson can maintain his  improvement through the season, it would be the 20th biggest increase ever.


Table 1: All-Time Best One-Year Improvements in OPS

Player	Team	Year 1	OPS 1	Year 2	OPS 2	% change
Cito Gaston	SDN	1969	0.585	1970	0.907	55.1
Rico Petrocelli	BOS	1968	0.667	1969	0.992	48.8
Carl Furillo	BRO	1952	0.655	1953	0.973	48.6
Al Kaline	DET	1954	0.652	1955	0.967	48.3
Wayne Garrett	NYN	1969	0.558	1970	0.811	45.4
Dusty Baker	LAN	1976	0.605	1977	0.876	44.8
Jimmy Wynn	HOU	1971	0.596	1972	0.860	44.2
Roy Campanella	BRO	1954	0.686	1955	0.978	42.6
Adrian Beltre	LAN	2003	0.714	2004	1.017	42.4
Clay Dalrymple	PHI	1961	0.575	1962	0.809	40.7
Al Zarilla	SLA	1947	0.621	1948	0.871	40.3
Tim Wallach	LAN	1993	0.612	1994	0.859	40.2
Ray Powell	BSN	1920	0.595	1921	0.830	39.5
Darin Erstad	ANA	1999	0.683	2000	0.951	39.3
Al Cowens	KCA	1976	0.639	1977	0.885	38.6
Mike Mitchell	CIN	1908	0.585	1909	0.808	38.1
Horace Clarke	NYA	1968	0.512	1969	0.706	37.8
Richard Hidalgo	HOU	1999	0.748	2000	1.028	37.3
Mike Epstein	WS2	1968	0.704	1969	0.965	37.0
Austin Jackson	DET	2011	0.690	2012	0.943	36.7

Data Source: Baseball-Databank.org

The biggest step up in OPS was by Padres outfielder Cito Gaston, who raised his OPS from  .585 in 1969 to .907 in 1970, an incredible 55% improvement.  Unfortunately, Gaston fell back to .650 in 1971 and never approached an OPS of .800 again.  The biggest jump in the American League was by Red Sox shortstop Rico Petrocelli who went from .667 in 1968 to .992 in 1969, a 49% change.  That one warrants an asterisk as 1969 was the year the pitchers mound was lowered from 15 inches to 10 inches.

The biggest OPS improvements for Tigers players are shown in Table 2 below.  Jackson's 37% increase would be the second largest in team history to Hall of Famer Al Kaline.  Kaline went from .652 in 1954 to .967 in, a 48% change.  Unlike many of the players on Table 1, Kaline was able to maintain much of his improvement going forward (although 1954 may have been his best season).   


Table 2: Top Ten One-Year Improvements for Tigers

Player	Year 1	OPS 1	Year 2	OPS 2	% change
Al Kaline	1954	0.652	1955	0.967	48.3
Austin Jackson	2011	0.690	2012	0.943	36.7
Bobby Higginson	1995	0.721	1996	0.982	36.1
Harry Heilmann	1920	0.787	1921	1.051	33.5
Bill Freehan	1973	0.636	1974	0.840	32.1
Ralph Young	1919	0.562	1920	0.729	29.7
Bill Freehan	1966	0.646	1967	0.835	29.4
Sam Crawford	1910	0.756	1911	0.964	27.5
Alan Trammell	1989	0.648	1990	0.826	27.4
Norm Cash	1960	0.903	1961	1.148	27.1

Data Source: Baseball-Databank.org

Can Jackson keep it up for the whole season and into future seasons? His walk and strikeout rates are both significantly better than past seasons which is generally a very good sign.  His increase in power does not surprise scouts who had previously said he had the potential to hit more home runs.  His inflated .406 BABIP would suggest that he'll regress a bit by the end of the season, but much of his improvement seems legitimate.  At this point, it looks historic.