West Ham manager Avram Grant is facing the sack unless he wins at least one of the relegation-threatened club's next three games, BBC Sport understands.
The Premier League's bottom team, who are four points adrift of safety, face Blackburn and Fulham away, before meeting Everton on 28 December.
A source said this allows the club to make best use of the transfer window.
"If we didn't win once by the turn of the year then there would have to be a change before the start of the January transfer window to give a new manager a chance to make the changes he wanted," the senior source told BBC Sport.
Can't see them getting owt from Rovers or an Everton side looking to bounce back from a 3-0 beating at Eastlands - Fulham or bust?
Fat Sam back in business at the Boleyn? Walmai?