Laz Diaz Ejects Fan Who Threw Ball Toward Umpire

2B Umpire and Crew Chief Laz Diaz 'ejected' a fan for throwing a baseball onto the playing field, which landed near the umpire, during Saturday's Rockies-Giants game in San Francisco. Although technically an order for stadium personnel to remove the fan rather than a direct ejection, Diaz's ruling involves both the Official Baseball Rules and, locally, the Oracle Park Guest Code of Conduct.

All MLB stadiums have rules for spectators similar to Oracle Park's, which states, "guests entering, or attempting to enter, the playing field, or other areas which they are unauthorized to enter, or who throw (or attempt to throw) objects, with the exception of home run balls, in the stands or onto the field, are subject to ejection and prosecution. Fans interfering while a ball is in play are subject to ejection."

Although umpires are not specifically empowered with the authority to 'eject' fans, Official Baseball Rule 8.01(b) makes clear that umpires can order stadium personnel remove the fan: "Each umpire has authority to order a player, coach, manager or Club officer or employee to do or refrain from doing anything which affects the administering of these rules, and to enforce the prescribed penalties."

Spectators are #1—the most permissive spot—on the tolerance hierarchy for officiating, but getting physically involved with the game crosses that line. 

In 2017, Joe West, umpiring first base, ordered a game temporarily halted after a fan threw a ball from the stands and hit West in the back of his head.

Video as follows:

Alternate Link: Diaz orders fan removed for throwing ball onto field, nearly hitting him