Pogba's agent, Mino Raiola, admitted the teenager's future at Old Trafford was now "precarious" after he was told to train alone after being left out of the squad for the second leg of the Europa League tie against Ajax.
Raiola and United refused to confirm or deny that Pogba, out of contract in the summer, was excluded from first-team training last Friday.
"It is a precarious situation. It is difficult," Raiola said. "United want him. It is up to the boy to make some decisions."