The utility provider signed a three-year deal in 2009 worth £21m to become sponsor of the League, replacing Coca-Cola. The deal was overseen by then-marketing director Kevin Peake, who left Npower last year.
It is understood that the energy company has carried out a brand and strategy review overseen by its top marketer, Debbie Britton, who joined from AXA in January, and is now looking to take its marketing in a 'different direction'.
The period of exclusivity in negotiations between the Football League and Npower has expired, meaning the League is now free to talk to other brands. Negotiations will be led by its chief commercial officer, Richard Heaselgrave.
The Football League's three divisions are the Championship, League One and League Two; the Championship feeds in to the Premier League.