Although "umpire ejects grounds crew" might be an attention-grabbing headline, Crew Chief Tim Timmons' order for Baltimore's tarp crew to exit the field during play Wednesday vs New York was actually an invocation of Official Baseball Rule 8.01(e) regarding umpire qualifications and authority.
To review, Timmons noticed Baltimore's grounds crew had gathered behind the on-field tarp during a 9th inning Replay Review and, despite impending rain, directed the crew to leave the playing field.
The umpire's authority for such a call is found in OBR 8.01(e), which states, "Each umpire has authority at their discretion to eject from the playing field (1) any person whose duties permit their presence on the field, such as ground crew members, ushers, photographers, newsmen, broadcasting crew members, etc., and (2) any spectator or other person not authorized to be on the playing field."
As for the why of Timmons' decision, the answer is twofold: player/staff safety and interference.
The sheer number of people that staged and crouched behind the tarp, on the field, created a potential hazard. For instance, if a ball were to have been hit toward the tarp, or, moreover, a player attempted to make a play at the tarp, the assembled Orioles grounds crew would have no means of escape from their positions. This means that a generally brilliant diving play by an outfielder at the tarp would instead likely result in injury, either to the player and/or grounds crew.
With the proven athleticism of MLB players, this remained a key possibility.
The other concern is interference wherein a ball that might usually bounce into and out of the tarp area might instead connect with a grounds crew staffer and get stuck. This likely would be unintentional interference to be sure, but given the option of potential unintentional interference or no interference, the preference is clear.
Finally, as for the inclement weather concern, the rain fell in Baltimore for nary a few minutes after which it let up: by the time Yankees pitcher Aroldis Chapman recorded the final strikeout of the night several outs after the tarp event, it was not raining anymore.
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