The midfielder was forced off just five minutes into the 2-1 win over Colchester with a damaged toe. He sustained the injury in a clash with former Hammers' striker Freddie Sears.
Nolan received intensive treatment on the touchline but was unable to go on.
"It is very sore and we can only hope it is just bruising and nothing is broken," said West Ham assistant manager Neil McDonald.
Nolan will have a scan today and Sam Allardyce is hoping his influential skipper will be fit for the tour of Germany and start of their Premier League campaign next month.