Rooney had already weathered negative publicity about revelations that he had sex with old age prostitutes, but managed to keep his sponsors on board.
Now the Sunday Mirror reports that Coca-Cola has written to the 19-year-old star to demand an explanation about his behaviour, and Nike has also done the same.
Coke has a £1m deal with Rooney, scheduled to last until 2006. Nike signed the star on a 10-year deal, worth £5m. He is also backed by the computer games company Electronic Arts and makes £50,000 a week playing for Manchester United, which yesterday beat Newcastle 4-1 in the FA Cup semi-final.
The trouble stems from an incident last weekend at a nightclub in Alderley Edge, Cheshire. Tabloid reports say that Rooney was seen slapping McLoughlin, who left the club in tears.
Rooney is known for his short temper and being agressive on the pitch and was also accused recently of punching a student in a nightclub, but this story was said to have been fabricated after the student withdrew the allegations.
Rooney and McLoughlin have since been photographed publicly making up and McLoughlin has said that it was just a small row.
The Sunday Mirror reports that Coca-Cola wants Rooney to issue a public denial, or else it will end its sponsorship.
It quotes a source from Coke in the US saying: "It was bad enough that he had been caught sleeping with hookers. But we forgave him as he was young and he admitted he had been foolish. But striking a woman is unacceptable and we will not tolerate it. It's totally offensive."
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