Clemente obvious choice for best outfield arm
But there's more to great throwing than arm strength and Web Gems. There's also accuracy and consistency, and Bo Jackson wasn't long on either quality. Jackson never racked up more than 11 assists -- or "baserunner kills," if you prefer -- in a season, and it wasn't because the baserunners were too afraid to run. Jackson's arm certainly ranks among the most impressive of his era. But it was not one of the best.
So should we look just at assists? We can't. Care to guess who owns the record for career assists by an outfielder? Nope, not Roberto Clemente. Or Willie Mays, or Hank Aaron. The record is held by Tris Speaker, with 449 career assists. Speaker did play forever, but he also played roughly 30 paces beyond second base, which gave him an immense number of opportunities to kill baserunners. Ty Cobb, who didn't have a particularly good arm, is No. 2 on the all-time list with 391 assists.