Chelsea said on Wednesday they had made a bid for Manchester United star Wayne Rooney, which has reportedly been rejected despite growing signs the England striker is unhappy at Old Trafford.
The London club took the unusual step of confirming a bid - for an undisclosed sum - after British reports said Juan Mata or David Luiz had been offered as a make-weight.
"Chelsea Football Club can confirm that yesterday it made a written offer to Manchester United for the transfer of Wayne Rooney," said a Chelsea statement on Wednesday.
"Although the terms of the offer are confidential, for avoidance of doubt and contrary to what is apparently being briefed to the press in Sydney, the proposed purchase price does not include the transfer or loan of any players from Chelsea to Manchester United," it said.
The wording of the statement takes an apparent swipe at Manchester United, who are currently in Sydney during their pre-season tour with a large contingent of British journalists.
It follows reports that Chelsea offered STG10 million ($A16.51 million) for Rooney, with either midfielder Juan Mata or defender David Luiz thrown in.
Rooney's future has been the subject of considerable speculation since May, when departing United manager Alex Ferguson said he had asked for a transfer. The statement was denied by Rooney.
However, the England striker has also refused to confirm his plans and the rumour mill went into overdrive when he left United's Asian tour on the first day after picking up a minor hamstring injury.
Chelsea boss Jose Mourinho poured fuel on the fire by admitting he admired Rooney "very, very much", forcing Manchester United manager David Moyes to repeat his assertion that the player is not for sale.
"It's hard to keep repeating myself but I will do - Wayne's a Manchester United player and will remain that," Moyes said.
But on Tuesday Rooney was reported to be "angry and confused" about separate comments from Moyes indicating that he would be used as back-up to fellow striker Robin van Persie next season.
News of Chelsea's bid broke as Mourinho began his second spell in charge with a friendly in Bangkok against the Singha All-Star XI.
The same team handed Moyes a losing start to his Manchester United reign when they shocked the Premier League champions 1-0 on Saturday.
Mourinho's Chelsea are rated as the biggest threat to Manchester United's title defence as Moyes attempts to follow Ferguson's 27-year, 38-trophy reign.