Rules Reference

Definitions
(interference (c))
Definition of "umpire interference"
5.06(c)(2) Plate umpire interferes with catcher's throw
5.06(c)(6) Fair batted ball touches umpire in fair territory
5.05(b)(4) Fair batted ball touches umpire before passing a fielder
5.05(a)(4) Fair batted ball touches umpire after passing a fielder
6.01(f) Umpire accidentally touched by thrown ball