Mystery of the Vanishing Umpires - Ballou & Brown Go Missing

During MLB umpire Chris Conroy's rehab assignment last Sunday in Triple-A, two umpires mysteriously vanished from the Charlotte Knights vs Lehigh Valley IronPigs game in the 4th inning and haven't worked a game—neither minor nor major league—ever since. An umpire leaving mid-game without any apparent injury is rare, but two? What happened to MLB fill-in umpire Brock Ballou and fellow MiLB colleague Matt Brown?

Crew Chief Edwin Jimenez, who began the game as the third base umpire, left the field in the 4th inning to put on his plate gear. By the top of the 5th, both Ballou and Brown had left the field, an unnamed third umpire was added to the Jimenez/Conroy crew, and the game continued only to end on a controversial out call by the mystery umpire, likely an emergency standby or alternate called upon in case the crew ran short (MiLB crews with multiple call-ups [Jimenez, Ballou, for this crew] are susceptible to this due to the nature of these call-ups traveling to work MLB games...if the crew falls to two, an emergency local may be called on to fill in until a Minor League umpire arrives [usually a day later]).

Further complicating matters, Official Baseball Rule 8.02(d) states, "No umpire may be replaced during a game unless they are injured or become ill," which means that the league office has no rules authority to remove an umpire during a game...of course, that assumes the league is actually following the rules of the game, which may actually not be the ironclad defense it might first appear to be.

We've seen one umpire exit, usually due to injury, but two at practically the same time? And for both Ballou and Brown to have not worked a single MiLB or MLB game in nearly two weeks? MiLB umpires don't take vacations like their major league counterparts.

An umpiring mystery, indeed! | Video as follows:

Alternate Link: Umpires Ballou and Brown leave during middle of game, haven't officiated since