Jose Mourinho has told Morgan Schneiderlin that he can leave United in January.
Schneiderlin was signed by Mourinho's predecessor Louis van Gaal for £25 million from Southampton last summer.
The Frenchman joined United as part of a double swoop with Bastian Schweinsteiger in a revamped engine-room partnership that was dubbed 'Schmidfield'.
However, he has played only eleven league minutes this season and West Brom have made a bid of £15 million for the Frenchman in January.
Baggies manager Tony Pulis confirmed his club's interest in the player - who has 15 caps for France - while Mourinho said he would not "stop him leaving" - despite the prospect of a £10 million loss - if the club's board agreed the deal.
Schneiderlin was an instrumental figure in the Saints rise from the third tier to qualification for Europe, and shone under Ronald Koeman, but was never able to replicate that form at Old Trafford.
Everton are also thought to be interested and Schneiderlin's future now seems certain to lie away from Old Trafford.
He played 40 times for United last season during a dire campaign under LVG - scoring once - but, despite Jose's rotational policy, has slipped down the pecking order under the new boss.
It's difficult to know exactly what went wrong for the player at United: was it a case of him being another LVG flop, was he just not good enough or was he a victim of Jose's desire to make this United side his own?
Schneiderlin can also claim to have fallen victim to his own team mates success with United's midfield looking the strongest it has for years.
Michael Carrick continues to defy his age with a series of impeccable performances, Ander Herrera has been impressively consistent and Paul Pogba's world record fee makes him undroppable.
Marouane Fellaini has often been preferred ahead of him, Schneiderlin has barely even made the bench and was never going to become a first-team regular at the club.
West Brom will offer him that and a move to the West Midlands side looks the best outcome for him, United and the Hawthorns outfit,
Memphis Depay is another United player who has fallen out of favour and has also been linked with a move away.
Everton are again said to be interested in securing the winger's services but Koeman has remain tight-lipped on any potential deal and the Dutchman's future remains in the balance.
Mourinho continues to show ruthlessness as he makes this squad his, with Schneiderlin - and possibly Memphis - victims of the previously failed managerial regime.