pitcher, hurler, twirler

(baseball or softball) the person who does the pitching; "our pitcher has a sore arm"

• left-handed pitcher, left-hander, lefty, southpaw — a baseball pitcher who throws the ball with the left hand
• right-handed pitcher, right-hander — (baseball) a pitcher who throws with the left hand
• reliever, relief pitcher, fireman — a pitcher who does not start the game
• screwballer — (baseball) a pitcher who throws screwballs
• starting pitcher — (baseball) a pitcher who starts in a baseball game

• ballplayer, baseball player — an athlete who plays baseball
• thrower — someone who projects something through the air (especially by a rapid motion of the arm)