Second Base: Rogers Hornsby, 91.5 WAR
Playing 13 seasons with the St. Louis Cardinals from 1915-1926, and once more for half of '33. 1942 National Baseball Hall of Fame inductee Rogers Hornsby arguably paved the way for what it meant to "be a Cardinal". He was Albert before Albert. Musial before Musial. He was a 5-11, 175-pound second baseman that could hit a baseball a country mile.
Hailing from Winter, Texas, Rogers Hornsby had some of the most absurd stat lines you will ever see not only for a second baseman, but for any player in baseball history. He hit over .400 in three separate seasons, had over 200 hits in five different seasons, and slugged over .700 twice! Mr. Hornsby, often called by umpires around the league because of the respect he commanded, earned an MVP of his own (1925) and the elusive Triple Crown twice in his Cardinals career ( 1922, 1925). 1922 might be one of the most incredible statistical seasons you can find batting .401 with 42 home runs, and 152 RBIs to go along with 43 doubles, 250 hits and, 141 runs scored. Think about that. His .424 batting mark in 1924 is a 20th-century National League record. The man was born to hit a baseball.
Not only did he hit like a maniac, the Cardinals organization and Branch Rickey were endeared with Hornsby enough to name him player/manager halfway through the 1925 season. Rogers then went on to lead the Cardinals to their first-ever World Series victory, 4 games to 3, in an all-time classic over the New York Yankees in 1926 by tagging out Babe Ruth trying to steal 2nd base in the bottom of the ninth.
Hornsby and the team parted ways in 1926 citing his stubborn nature and at times overbearing personality. He then went on to play for the New York Giants, Boston Braves, and rival Cubs before returning in 1933 to St. Louis. He played half a season in Cardinals' red before being released midseason and signed by the St. Louis Browns as a player/manager where he would finish his career in 1937.
Although Hornsby played the better part of 1915-1919 as the SS for the Cardinals, his 991 games at second base when he took over full-time in 1920 puts "Rajah" atop the second base WAR list. In fact, it doesn't even really come close as Frankie Frisch comes in second at 33.8.