Prosecutors announced Monday that they were not filing charges against San Francisco Giants pitcher Sergio Romo after he was detained at McCarran International Airport in Las Vegas on New Year's Day, team spokeswoman Shana Daum said.

Romo, who was instrumental in the Giants' run to their second World Series title in three years, was detained and cited for a violation of airport rules, Las Vegas police Officer Marcus Martin said.

Police said Romo became agitated with Transportation Security Administration agents, was standing in an aggressive stance and did not back down when police officers arrived.

The right-handed pitcher was cited and released. It is unclear what the reason was for the encounter, Martin said.

The Clark County District Attorney's Office was not immediately available Monday for comment.