Sporting wants Rubén Amorim to stay until after the international break, but wants to leave before the clash with Manchester City.
Manchester United's hopes of bringing in Ruben Amorim as manager as soon as possible have hit a major roadblock.
United are in advanced talks with Sporting after verbally agreeing personal terms with Amorim to succeed the sacked Erik ten Hag.
It was expected within the Old Trafford hierarchy that Amorim would be appointed in time to lead the team into the Premier League clash at home against Chelsea on Sunday.
However, this is highly doubtful as the 39-year-old has a 30-day notice period in his contract, talkSPORT understands.
Sporting want to keep Amorim in the job until the international break in November, but Man United are in talks with the Portuguese champions to bring him in sooner.
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The incoming Red Devils coach would prefer to have his Sporting swan song on Friday night when they face Estrela Amadora in the Primeira Liga, but he wants to be respectful of his club.
It is also understood that Amorim would prefer to leave before Sporting face Manchester City in the Champions League on Tuesday night.
Amorim had been identified as a possible successor to pep guardiola in city of manchesterbut sources in Portugal say he was not willing to wait for the Spaniard to make a decision on his future.
City insiders say Amorim's style of play is not a perfect fit for their team and there is also growing confidence that Guardiola will stay for at least one more season when his contract expires in the summer.
United met with Amorim last week to lay the groundwork for him to replace Ten Hag, having decided they were not progressing quickly enough under the Dutchman in terms of performances and results.
Meanwhile, separate negotiations are underway over the addition of three backroom staff, including long-term assistant Carlos Fernandez.
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