heavy hitter

noun3

1. •
   A player with a favorable batting average who is especially good at hitting the ball deep into the outfield or farther.

   • This year's heavy hitter is Bobby Bonilla, the Pirates' slugger who's seeking to hit the biggest home run of his life. — 1991
2. •
   Someone or something of considerable importance; a person who is a major decision maker or capable achiever; an especially significant organization or an especially functional object.

   • Even Mrs Clinton, the heavy hitter, will need every ounce of her formidable powers. — 1993
3. •
   In any sport, a strong, physical player who is particularly effective.

   • On defense I always try to pair a good body-checker with a sound, steady player; for example, Ted Harris, a heavy hitter, with J. C. Tremblay, a clever defenseman. — 1967