A knuckleball or knuckler is a baseball pitch thrown to minimize the spin of the ball in flight, causing an erratic, unpredictable motion. The air flow over a seam of the ball causes the ball to change from laminar to turbulent flow. This change adds a deflecting force to the baseball, making it difficult for batters to hit but also difficult for pitchers to control and catchers to catch; umpires are challenged as well, as the ball's irregular motion through the air makes it harder to call balls and strikes. A pitcher who throws knuckleballs is known as a knuckleballer.

Robert Allen Dickey is an American former professional baseball pitcher. He played in Major League Baseball (MLB) for the Texas Rangers, Seattle Mariners, Minnesota Twins, New York Mets, Toronto Blue Jays and Atlanta Braves.