According to US Weekly, the decision is to support footballer Colin Kaepernick who is the former San Fransisco 49ers quarterback. Sources told the magazine that the NFL really wanted Rihanna to perform but she turned them down for Kaepernick.
Kaepernick started a protest in 2016 to challenge the killings of African-Americans in America. His cause soon attracted attention and many other footballers, celebrities and activists have declared support for him. He opted out of his contract in 2017 and is now team-less.
