The "Royals" singer, whose new record "Melodrama" was nominated for album of the year, was only offered a chance to sing part of a Tom Petty tribute song at the music-awards show in Manhattan on Sunday, TMZ reported.
Lamar beat Jay-Z in all of his three wins - best rap song, performance and music video for "Humble".
We already know what song dynamic duo Luis Fonsi and Daddy Yankee are going to perform, but the question is, will Justin Bieber or even JJ Lin maybe make an appearance? The other big awards of the night - song and record of the year - also are dominated by hip-hop, R&B and Latin music. "Despacito" is in competition for Record of The Year and Song of The Year. "So when you look at the work that's been done, and Jay would be one example, and there's that level of excellence, we have a very sophisticated voting membership that is able to recognize that".
Lionel Messi Admits One Regret About Barcelona's January Signing of Philippe Coutinho
However, the hosts were not as clinical in the first half so Valverde sent on Paulinho and then gave Coutinho his Barcelona debut. The Brazilian midfielder came on as a 68th minute substitute for Andres Iniesta - we'll let you process the symbolism there.
Lamar is expected to open Sunday's show which will also feature live performances by U2, Cardi B, Pink, Miley Cyrus, Sting, Sam Smith and many others.
Musicians have started to arrive on the red carpet wearing white roses in a display of solidarity with the anti-sexual harassment Me Too movement.
Kesha, who earned her first pair of Grammy nominations for an album reflecting her battle with former producer and mentor Dr. Luke, will honour victims during her performance.
And country artists Brothers Osborne, Eric Church and Maren Morris, who appeared at the Las Vegas country music festival where 51 people were killed and more than 500 were wounded last October, will mark the victims of gun violence and extremist attacks at music events.