Using baseball writer Rob Neyer's definition, this gallery includes any pitcher "who would not have been in the majors without his knuckleball, or whose knuckleball was considered his best pitch, at least for a time."
R.A. Dickey, the majors' only active knuckleball pitcher, became the first knuckleballer to win a Cy Young. Dickey's career has completely transformed since he joined the New York Mets, a distinction owned by few players. Before joining the Mets in 2010, Dickey operated primarily as a spot starter and frequently bounced between Triple A and the majors, with modest single-season MLB highs for wins (nine), ERA (4.62) and WHIP (1.48). Since joining the Mets, he has set career highs in all of those categories. In 2012, Dickey won 20 games (five of them complete, three of them shutouts) with a 2.73 ERA, 1.05 WHIP, and 230 strikeouts. From May 27 through June 18, Dickey allowed no earned runs over five starts, and through 54.2 innings pitched he struck out 71 batters with just six walks.