The striker hurt his right foot during his first full training session since regaining his fitness from a heel problem and will now see a specialist.
The club has revealed that the damage is in the same part of his right foot as his previous injury and the striker will now be examined by a specialist. West Ham gave no timeframe regarding Carroll's absence.
The 24-year-old Carroll was forced out of England's post-season friendlies in May with a heel injury and has yet to make an appearance for Sam Allardyce's side this season. Following a season-long loan spell at Upton Park in which he scored seven goals in 24 Premier League appearances, Carroll completed a permanent move from Liverpool to West Ham in June.
Allardyce is continuing his efforts to sign another striker, with the club reportedly competing with Arsenal for Romania striker Ciprian Marica, who was released by Schalke this summer.
Carlton Cole, who was not offered a new deal by West Ham at the end of last season, has also been on trial with Allardyce's side.
West Ham has also been linked with a move for former Fulham forward Mladen Petric, who is currently available on a free transfer.