Andy Carroll will fly to Holland today to see a specialist after his latest injury setback.
The £15.5million West Ham striker is expected to be out until the New Year after popping his troublesome heel in training earlier this week.
It will still be days, if not weeks before will be able to determine exactly how long Carroll will be out.
But they are resigned to losing the 24-year-old for the first half of the new season.
In a statement the club said: “West Ham United can confirm Andy Carroll suffered an injury to his right foot during his return to full training.
“Although it is in the same part of his foot as his previous injury, it is a new injury and therefore there will be no prognosis until he has seen a specialist.”
The Hammers have responded to the blow by moving swiftly yesterday to on a deal until the end of the season.
Petric had been released by Fulham in the summer after scoring five goals in 23 appearances for the west Londoners.
The Croatian said: “’I’m very happy, excited and looking forward to training with the team and to the first game.
‘I know [the Premier League] and I’m happy to be back in the Premier League, because it’s a fantastic league and I’m really looking forward to being part of this team and this Club.
‘There are a lot of good players here and I’m happy to be part of such a good team and I hope we can all celebrate my first goal for West Ham as soon as possible.”