The "Rude Boy" singer went on a "hysterical" outburst after experiencing great displeasure with her pre-show rehearsal,sources told TMZ.
It's unclear what exactly triggered the apparent incident, but the gossip site reports Rihanna was very upset and screaming loudly.
The 27-year-old singer was scheduled to perform her new hit, "Kiss Me Better," off of her latest "Anti" album at the Los Angeles-based award show, but she dropped out just hoursbefore the show, claiming she had a bad case of bronchitis.
Her rep told the Daily News that Rihanna's doctor told her to rest her voice for 48 hours or else she could risk damaging her vocal chords.
"The antibiotics she has been on for three days did not kill the infection adequately therefore she cannot perform safely," the rep said.
But sources told TMZ that Rihanna's voice sounded fine at her pre-Grammys rehearsal. The "We Found Love" artist also sounded flawless when she performed at Lionel Richie's charity event two days before the prestigious award show.
Rihanna apologized for missing the show on Monday evening on Twitter, writing, "So sorry I couldn't be there. Thanks Grammys and CBS for your support tonight."
She did not appear on the red carpet at the Grammys on Monday evening, and TMZ reports she went home after the rehearsal because she was too upset to even stay and watch the show.
This is the second time Rihanna has canceled a performance at the Grammys. She also pulled out in 2009 after singer Chris Brown, her boyfriend at the time, was charged with assaulting her. He pleaded guilty to felony assault later that year.