Umtiti was linked with United last summer but signed a new contract with Barcelona in June.
The 25-year-old has started nine games in La Liga and the Champions League combined this season however, with a knee injury restricting his opportunities under Ernesto Valverde.
That has influenced Barca’s targeting of De Ligt, who they view as Gerard Pique’s long-term replacement.
The Daily Mail report that Umtiti ‘is a player for whom they would listen to offers’ as they seek to raise enough funds to sign the Dutchman.
Ajax have already arranged a deal to sell Frenkie de Jong to Barca for €85million and would want the same amount for centre-half De Ligt.
Offloading former United target Umtiti to Old Trafford would therefore raise enough money to fund that deal.