Rihanna has abruptly canceled her planned performance tonight (Feb. 8) at the 51st annual Grammy Awards at Los Angeles' Staples Center, according to an announcement from the Recording Academy, which did not provide further details.

Al Green, who won two R&B Grammys during the pre-telecast, will reportedly replace Rihanna in the lineup.

Speculation is rampant that the cancellation is connected to an incident that occurred early this morning involving Rihanna's boyfriend, R&B star Chris Brown.

The Los Angeles Police Department is seeking Brown on a domestic violence felony battery report after he began arguing with the unnamed passenger in a car, said to be Rihanna. The argument escalated after they exited the vehicle but Brown wasn't at the scene by the time police arrived.

Rihanna performed early this morning at Timbaland's pre-Grammy party.

For full coverage of the 51st annual Grammy Awards, click here.