Answer: No catch; dead ball; ball contacting umpire’s mask is considered as contacting ground, hence, uncaught foul ball. (BB & SB - Rule 5, Sec. 1, Art. 1 (d-3))
Question: Left handed batter his fair line drive, which deflects off first baseman’s glove and contacts base umpire behind the first baseman and is caught in flight by the second baseman. Legal catch? Live/dead ball?
Answer: Live ball, no catch; batted ball remains in play as deflected fair ball contacting umpire is considered as having touched the ground. (BB - Rule 2, Sec. 5, Art. 1 & Rule 2-9-1; SB - Rule 2. Sec. 9, Art. 5 (e) and Rule 2-20-1(d))