Formula One supremo Bernie Ecclestone believes 2008 world champion Lewis Hamilton is now unsure whether to leave McLaren or join Mercedes.
"I don't think he knows what he will do," Ecclestone told ESPN.
"These last couple of races he has been doing very well. Before that, why he was upset I don't know, but he was definitely going to move no matter what.
"He had made his mind up he was going. Whether he has changed now I don't know."
Hamilton was initially offered a pay cut of a third on his £10million-per-year ($16.2 million) deal by McLaren, putting him on a par with team-mate Jenson Button.
That was understood to be McLaren's final offer, however, it has now been suggested the team have increased that by a further £2million ($3.2million).
The 27-year-old Briton is fourth in the overall standings, 52 points behind leader Spaniard Fernando Alonso heading into the last six races after suffering a gearbox failure during the Singapore Grand Prix.
Hamilton has won three races this season, in Canada, Hungary and Italy, and finished on the podium in the opening three races in Australia, Malaysia and China.