Steve Dalkowski.

About Steve Dalkowski

Stephen Louis Dalkowski Jr., nicknamed Dalko, was an American left-handed pitcher. He was sometimes called the fastest pitcher in baseball history and had a fastball that probably exceeded 100 mph (160 km/h). Some experts believed it went as fast as 110 mph (180 km/h), others that his pitches traveled at less than that speed. As no radar gun nor similar device was available at games to measure the speed of his pitches precisely, the actual top speed of his pitches remains unknown. Regardless of its actual speed, his fastball earned him the nickname "White Lightning". Such was his reputation that despite his never reaching Major League Baseball (MLB), and finishing his Minor League Baseball career in Class B baseball, a 1966 article in The Sporting News about the end of his career was headlined "Living Legend Released".