Alex Rodriguez, 57, 2002
In 2001, his first year at the hitter-friendly Ballpark in Arlington, Rodriguez smashed 52 home runs, the most ever by a shortstop. The next year he set a new standard, helped in part by 12 apiece in July and August. A two-homer game on Sept. 5 against the Orioles carried him to 50, and by Sept. 14, the Rangers' 148th game, he had 55. That gave him a shot at Maris' AL record of 61, but Rodriguez could hit only two more, still a career high. In 2009, however, he admitted to having used PEDs during his three years in Texas from 2001 to '03, what he called his "loosey-goosey" period.