West Ham were thrashed 4-0 by Bayer Leverkusen in their final pre-season friendly, while new Manchester United goalkeeper Andre Onana was lobbed from the centre circle against RC Lens.
Growing unease among fans about West Ham's lack of signings will only have been heightened by their side's defeat.
There is understood to be a difference of opinion between manager David Moyes and technical director Tim Steidten.
A total of 13 Premier League teams were in pre-season action on Saturday.
The thrashing by German side Leverkusen - who were 3-0 up at half-time - will increase the scrutiny on Moyes' side before next Saturday's first league game at Bournemouth.