Avid baseball fans, baseball historians, and (for that matter) MLB network in some of its off-season programming are inherently inclined towards making lists of the best players through history at each position. The comprehensiveness and integrity of major league baseball's statistical record, which has been enhanced in recent decades by advanced statistical analysis, lends itself well to precisely this pursuit. But lists of the best players at each position are invariably limited by the nine individual positions on the field, so that a choice must be made on where to position players who were regulars at different positions, sometimes in the same season. For the most part, these decisions are made based on career totals of what position a given player played most often. Tony Perez, for example, even though his best years as measured by the wins above replacement (WAR) metric of player value were mostly when he played third base for the Reds, is generally listed as a first baseman on career lists because he played 70 percent of his games at that position. I propose, therefore, that it might be useful to distinguish players who were core regulars on their teams at multiple positions from those clearly identifiable with a specific position.
"Multi-position regulars" can be grouped into two broad categories, each with its own subset. The first category are players who started at multiple positions for most, or the totality, of the best years in their career. In some cases, their versatility made them prime candidates to switch positions from one year to the next, or even within seasons, depending on the needs of their team. In others, their switching positions was more a matter of offsetting defensive liabilities (which often they carried from one position to another) by their must-have-in-the-lineup batting prowess. Two of baseball's historically greatest players were multi-position regulars during the best years of their careers--Stan Musial, who alternated between the outfield and first base his entire career (often in the same season), and Harmon Killebrew, who did the same between first and third (and even the outfield for two years). Neither played any four straight years as a regular exclusively at one position. Musial's first three years were in the outfield, his next two (after spending 1945 in the military) primarily at first, then two as an outfielder, two seasons (1950 and 1951) alternating between first and the outfield, the next three in the outfield, 1955 at first, 1956 at first and in the outfield, and the next three primarily at first before his career began to wind down with Stan the Man not-quite full-time. Killebrew's career progression as a regular began with one season at third (1959), followed by two alternating between first and third, two in the outfield, and all his remaining years at either first or third.
The subset of this first broad category are those players whose athleticism allowed them to play any number of infield positions, including up the middle. Gil McDougald, who had a ten-year career with the Yankees from 1951 to 1960, was the quintessential multi-position regular. McDougald gave Casey Stengel--the only major league manager he ever played for--the prized redundancy the Old Perfessor coveted for his infield. McDougald could, and did, play anywhere in the infield except for first base, always fielding his position well and remaining a dangerous hitter all the while. After platooning at third base and also playing second in his rookie season, McDougald was the Yankees' regular third baseman in 1952 and 1953, moved over to second base the next two years when Billy Martin was in the Army, was the Yankees' primary shortstop in 1956 and 1957 after Phil Rizzuto's first two successors didn't quite work out, and was back to being the second baseman in 1958 before ending his career coming off the bench. In the 1,221 games McDougald started for the Yankees, 516 (42 percent) were at second, 436 (35 percent) at third, and 269 (22 percent) at short.
The second category of multi-position regulars are the crossover years when a player switched from one position to another. Robin Yount, who shifted from shortstop to center field in 1985, and Alex Rodriguez, who shifted from shortstop to third base when he came to the Yankees in 2004, are classic examples of crossover players. Crossover years for analytical purposes, however, are limited to a maximum of six years, including no more than three years at either position, so in many (if not most) cases, the best years of a player who changed positions are likely to be at one position or the other. Yount's best years as a player, for example, were at shortstop. A-Rod was one of the greatest shortstops in history in the first eight years of his career, and then became one of the greatest third basemen in history over the next five years (although how much of his "greatness" was "enhanced" appears increasingly not so much an open question as a question of, by how much).
The subset of this second broad category are players whose best years included their crossover years from one position to another. Johnny Pesky, for his best years of 1942 to 1949 (not including three years, 1943-45, serving in World War II), is a compelling example of such a player. After establishing himself as one of the American League's best shortstop in his first three major league seasons, with every expectation of a long career at the position, Pesky switched to third in 1948 when the Red Sox acquired power-hitting shortstop Vern Stephens. Babe Ruth, however, perhaps should be considered the premier player in this category during his Red Sox years of 1915 to 1919, whose transition from outstanding pitcher to outfielder to take advantage of his prodigious power began in 1918.
As outstanding as Miguel Cabrera has been for most of his career, if he continues playing at the level he is now, his best consecutive years as a player will have been 2009 through 2013. These years include his changing positions in 2012 from first to third so the Tigers could accommodate the acquisition of Prince Fielder to play first base. Other prominent multi-position regulars in recent years include infielder-outfielder Martin Prado, infielder Michael Young (from second to short to third), and infielder Placido Polanco (second and third).
Based on their best consecutive years as measured by the WAR metric, the five best multi-position regulars in the National League since 1901 were: 1) Stan Musial ; 2) Frankie Frisch from 1921 to 1927, playing all around the infield until finally settling full time as the second baseman for which he is remembered; 3) Roger Bresnahan, best known as an innovative catcher but who played mostly in the outfield in the first two of his best playing years from 1903 to 1908; 4) Frank Robinson from 1956 to 1960, playing primarily the outfield his first three years in Cincinnati and first base the next two before moving full-time back to the outfield; and 5) Dick, then known as "Richie," Allen alternating between third and the outfield from his rookie season of 1964 to 1969.
Ruth is arguably the American League's best-ever multi-position regular, followed by: 2) Killebrew; 3) Paul Molitor for his best years from 1987 to 1993, during which he transitioned from third base to become a designated hitter; 4) McDougald; and 5) Pesky.
A comprehensive listing of the best multi-position regulars in each league, successively over the 100 years of the twentieth century and through the first decade of this one, who played more than one position over any given five-year period can be found in Transparency Annex B of my online manuscript, www.thebestbaseballteams.com, at the following link: http://www.thebestbaseballteams.com/pdf/Revised_Best_Position_Methodology.pdf