NEW YORK (Reuters) - New York Mets reliever Francisco Rodriguez violated a protection order and will face additional charges on top of allegedly assaulting his father-in-law, a spokeswoman for the Queens District Attorney said on Tuesday.

Rodriguez, known as K-Rod, sent dozens of text-messages to his common-law wife Daian Pena, the spokeswoman said, in violation of a protection order issued following his August arrest.

The four-time All-Star pitcher appeared in Queens Criminal Court for a hearing but was told to expect criminal contempt charges at his next court appearance on October 7.

Rodriguez, 28, was taken into custody at the Mets ballpark Citi Field after an August 6-2 loss to the Colorado Rockies, during which Rodriguez grew visibly upset that he was not summoned from the bullpen to pitch.

Prosecutors said Rodriguez pinned his 53-year-old father-in-law, Carlos Pena, against a wall and punched him repeatedly.

In court on Tuesday, Assistant District Attorney Scott Kessler read some of the messages Rodriguez sent in which the pitcher appears to try to win Pena back.

"Daian, I understand that perhaps I made a mistake, the biggest mistake of my life for doing what I did but I love you," one message said.

Rodriguez attempted to leave the ballpark the night of the incident in his white Lamborghini but was called back to the clubhouse where he was arrested, the New York Post reported.

(Reporting by Basil Katz; Editing by Steve Ginsburg)