1) AL or NL official 2) NL arbiter 3) Arbiter 4) At home worker 5) Authority at home 6) Authority on diamonds 7) Ball caller 8) Ballpark arbiter 9) Ballpark authority 10) Ballpark figure 11) Ballpark judge 12) Ballpark official 13) Ballpark worker 14) Ballplayer ejector, at times 15) Balls and strikes caller Found on https://www.crosswordclues.com/clue/ump