"We felt the best course of action was to send him back to New Zealand for further assessment."
Anderson was sent for a MRI scan which revealed a new bone stress-related injury to his lumbar spine.
Further investigations are required for clarification.
A replacement is yet to be named.
The injury is also likely to curtail his contract with Somerset for the latter half of the England domestic Twenty20 competition.
It continues a unfortunate run of fitness for the all-rounder who fractured a finger playing for the Mumbai Indians during the Indian Premier League before they went on to triumph.