Randall David Johnson (born September 10, 1963), nicknamed "the Big Unit", is a left-handed American starting pitcher who currently plays for Major League Baseball's Arizona Diamondbacks.
The 6-foot-10 Johnson has been celebrated for having one of the most dominant fastballs in the game. He regularly approached, and occasionally exceeded, 100 miles per hour during his prime. However, his signature pitch is a hard, biting slider. Johnson has won the Cy Young Award five times, second only to Roger Clemens' seven.
For all active pitchers through the 2007 season, Johnson is first in strikeouts per nine innings pitched (10.78 -- which is also first for all pitchers in history) and hit batsmen (182 -- fourth all-time), first in strikeouts, second in hits allowed per nine innings pitched (7.14), second in shutouts (37), fourth in wins (288), sixth in ERA (3.22) and wild pitches (102), and seventh in won-lost percentage (.654). His 4,687 strikeouts are also first all-time among left-handed pitchers.