Isolated Power Single Season Leaders on Baseball Almanac

Single Season Leaders for Isolated Power

Isolated Power is a SABERmetric statistic that attempts to describe a hitter's overall effectiveness by measuring his ability to generate extra base hits. Isolated Power was created by baseball great Branch Rickey along with Allan Roth during the 1950's and they termed it Power Average. Isolated Power is calculated by substracting batting average from slugging percentage.

Important notes: 1,000 career games played are needed to make this list, raw averages are presented to further clarify the one-hundred greatest career isolated power averages of all-time, and a bold faced entry denotes that the player was active during the previous Major League season.

"My relationship (with the San Francisco Giants) has been up and down, but for the most part has been good. This year it's been exceptionally good. You walk into a store, and you run into little old ladies who've never seen a baseball game before in their whole life, telling you what a great accomplishment you have." - Barry Bonds on ESPN.com (Bonds finishes remarkable season with 73, 10/07/2001)

Isolated Power Single Season Leaders 'Top 100'
Name	Isolated Power	Year	Team	League	Rank
Barry Bonds	.536 (.53571)	2001	San Francisco Giants	NL	1
Babe Ruth	.472 (.47162)	1920	New York Yankees	AL	2
Babe Ruth	.469 (.46852)	1921	New York Yankees	AL	3
Mark McGwire	.454 (.45383)	1998	St. Louis Cardinals	NL	4
Barry Bonds	.450 (.45040)	2004	San Francisco Giants	NL	5
Barry Bonds	.429 (.42928)	2002	San Francisco Giants	NL	6
Mark McGwire	.418 (.41844)	1996	Oakland Athletics	AL	7
Mark McGwire	.418 (.41843)	1999	St. Louis Cardinals	NL	8
Babe Ruth	.417 (.41667)	1927	New York Yankees	AL	9
Mark McGwire	.410 (.41009)	1995	Oakland Athletics	AL	10
Sammy Sosa	.409 (.40901)	2001	Chicago Cubs	NL	11
Barry Bonds	.408 (.40769)	2003	San Francisco Giants	NL	12
Lou Gehrig	.392 (.39212)	1927	New York Yankees	AL	13
Babe Ruth	.386 (.38619)	1928	New York Yankees	AL	14
Jimmie Foxx	.385 (.38462)	1932	Philadelphia Athletics	AL	15
Jeff Bagwell	.383 (.38250)	1994	Houston Astros	NL	16
Barry Bonds	.381 (.38125)	2000	San Francisco Giants	NL	17
Frank Thomas	.376 (.37594)	1994	Chicago White Sox	AL	18
Albert Belle	.374 (.37363)	1995	Cleveland Indians	AL	19
Jim Thome	.373 (.37292)	2002	Cleveland Indians	AL	20
Babe Ruth	.373 (.37259)	1930	New York Yankees	AL	21
Mark McGwire	.372 (.37222)	1997	Oakland Athletics	AL	22
Mark McGwire	.372 (.37222)	1997	St. Louis Cardinals	NL	22
Babe Ruth	.372 (.37165)	1923	New York Yankees	AL	23
Mickey Mantle	.370 (.36965)	1961	New York Yankees	AL	24
Hank Greenberg	.369 (.36871)	1938	Detroit Tigers	AL	25
Hack Wilson	.368 (.36752)	1930	Chicago Cubs	NL	26
Babe Ruth	.366 (.36566)	1926	New York Yankees	AL	27
Luis Gonzalez	.363 (.36289)	2001	Arizona Diamondbacks	NL	28
Babe Ruth	.361 (.36106)	1924	New York Yankees	AL	29
Javy Lopez	.359 (.35886)	2003	Atlanta Braves	NL	30
Babe Ruth	.357 (.35714)	1922	New York Yankees	AL	31
Albert Belle	.357 (.35680)	1994	Cleveland Indians	AL	32
Jimmie Foxx	.356 (.35575)	1938	Boston Red Sox	AL	33
Barry Bonds	.355 (.35493)	1999	San Francisco Giants	NL	34
Larry Walker	.354 (.35387)	1997	Colorado Rockies	NL	35
Rogers Hornsby	.353 (.35317)	1925	St. Louis Cardinals	NL	36
Mickey Mantle	.353 (.35272)	1956	New York Yankees	AL	37
Babe Ruth	.353 (.35271)	1929	New York Yankees	AL	38
Ken Griffey, Jr.	.351 (.35104)	1994	Seattle Mariners	AL	39
Roger Maris	.351 (.35085)	1961	New York Yankees	AL	40
Travis Hafner	.350 (.35022)	2006	Cleveland Indians	AL	41
David Ortiz	.349 (.34946)	2006	Boston Red Sox	AL	42
Todd Helton	.349 (.34923)	2001	Colorado Rockies	NL	43
Ralph Kiner	.348 (.34791)	1949	Pittsburgh Pirates	NL	44
Jimmie Foxx	.347 (.34729)	1933	Philadelphia Athletics	AL	45
Sammy Sosa	.347 (.34720)	1999	Chicago Cubs	NL	46
Willie Stargell	.347 (.34674)	1973	Pittsburgh Pirates	NL	47
Manny Ramirez	.346 (.34624)	2000	Cleveland Indians	AL	48
Ryan Howard	.346 (.34596)	2006	Philadelphia Phillies	NL	49
Carlos Pena	.345 (.34490)	2007	Tampa Bay Devil Rays	AL	50
Kevin Mitchell	.344 (.34438)	1989	San Francisco Giants	NL	51
Rudy York	.344 (.34400)	1937	Detroit Tigers	AL	52
Lou Gehrig	.344 (.34370)	1934	New York Yankees	AL	53
Jim Gentile	.344 (.34362)	1961	Baltimore Orioles	AL	54
Ted Williams	.343 (.34286)	1957	Boston Red Sox	AL	55
Lou Gehrig	.343 (.34251)	1930	New York Yankees	AL	56
Jim Edmonds	.342 (.34228)	2003	St. Louis Cardinals	NL	57
Ken Griffey, Jr.	.342 (.34211)	1997	Seattle Mariners	AL	58
Lou Gehrig	.342 (.34197)	1936	New York Yankees	AL	59
Hank Aaron	.342 (.34184)	1973	Atlanta Braves	NL	60
Hank Aaron	.341 (.34141)	1971	Atlanta Braves	NL	61
Barry Bonds	.341 (.34137)	1993	San Francisco Giants	NL	62
Jim Edmonds	.341 (.34137)	2004	St. Louis Cardinals	NL
Brady Anderson	.340 (.34024)	1996	Baltimore Orioles	AL	64
Albert Pujols	.340 (.34019)	2006	St. Louis Cardinals	NL	65
Willie Mays	.340 (.33966)	1955	New York Giants	NL	66
Matt Williams	.339 (.33933)	1994	San Francisco Giants	NL	67
Sammy Sosa	.339 (.33904)	1998	Chicago Cubs	NL	68
Mike Schmidt	.338 (.33759)	1980	Philadelphia Phillies	NL	69
Willie McCovey	.336 (.33605)	1969	San Francisco Giants	NL	70
Babe Ruth	.336 (.33565)	1919	Boston Red Sox	AL	71
Barry Bonds	.335 (.33504)	1994	San Francisco Giants	NL	72
Jimmie Foxx	.334 (.33405)	1939	Boston Red Sox	AL	73
Reggie Jackson	.333 (.33333)	1969	Oakland Athletics	AL	74
Jim Thome	.333 (.33270)	2001	Cleveland Indians	AL	75
Willie Stargell	.333 (.33268)	1971	Pittsburgh Pirates	NL	76
Tony Clark	.332 (.33238)	2005	Arizona Diamondbacks	NL	77
Hank Greenberg	.332 (.33165)	1937	Detroit Tigers	AL	78
Alex Rodriguez	.331 (.33105)	2007	New York Yankees	AL	79
Larry Walker	.331 (.33105)	1999	Colorado Rockies	NL
Albert Pujols	.331 (.33099)	2009	St. Louis Cardinals	NL	81
Prince Fielder	.330 (.32984)	2007	Milwaukee Brewers	NL	82
Hank Greenberg	.330 (.32984)	1940	Detroit Tigers	AL
Manny Ramirez	.329 (.32950)	1999	Cleveland Indians	AL	84
Ted Williams	.329 (.32903)	1960	Boston Red Sox	AL	85
Juan Gonzalez	.329 (.32902)	1996	Texas Rangers	AL	86
Ted Williams	.329 (.32895)	1941	Boston Red Sox	AL	87
Mark McGwire	.329 (.32855)	1987	Oakland Athletics	AL	88
Willie Mays	.328 (.32796)	1965	San Francisco Giants	NL	89
Babe Ruth	.328 (.32772)	1931	New York Yankees	AL	90
Mike Schmidt	.328 (.32768)	1981	Philadelphia Phillies	NL	91
Ken Griffey, Jr.	.327 (.32701)	1998	Seattle Mariners	AL	92
Hank Greenberg	.327 (.32696)	1946	Detroit Tigers	AL	93
Joe DiMaggio	.327 (.32689)	1937	New York Yankees	AL	94
Albert Belle	.327 (.32677)	1998	Chicago White Sox	AL	95
Al Simmons	.327 (.32671)	1930	Philadelphia Athletics	AL	96
Derrek Lee	.327 (.32660)	2005	Chicago Cubs	NL	97
Albert Pujols	.326 (.32601)	2004	St. Louis Cardinals	NL	98
Todd Helton	.326 (.32586)	2000	Colorado Rockies	NL	99
Stan Musial	.326 (.32570)	1948	St. Louis Cardinals	NL	100
Name	Isolated Power	Year	Team	League	Rank
Current Through 2009 Season

Why is the Isolated Power statistic not used commonly? Should it be used more often? Is it better than on base plus slugging? Share your opinion on Baseball Fever where we have an entire forum dedicated to advanced statistics.

The American League single season record for isolated power was set in 1920 by Babe Ruth of the New York Yankees. The National League single season record for isolated power was set in 2001 by Barry Bonds of the San Francisco Giants.

Bonds, McGwire and Ruth are the only three (3) players in Major League history with a career isolated power mark greater than .299, but which one of these single season isolated power dominators is the career leader for isolated power?

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