1
general::
Also, have something on the ball. Be especially capable or efficient, as in These programmers really have a lot on the ball. This term originated in baseball, where it was used for throwing a pitch with exceptional speed, spin, or some other deceptive motion. [Slang; early 1900s]
American Heritage Idioms
2
general::
Phrase(s): on the ball
Inf. knowledgeable; competent; attentive. (See also have something on the ball.) • This guy is really on the ball. • If you were on the ball, this wouldn’t have happened.
McGrawhill's American Idioms And Phrasal Verbs