Buchanan said Bennett pulled up sore at training and while scans had ruled out a stress fracture the 24-year-old was set to sit out the Zimbabwe tour, which begins next month.
He said Bennett should be available for New Zealand's tour of Australia in November.
The Black Caps will play three one-dayers, two Twenty20 internationals and one Test against Zimbabwe.
Copyright AFP (Agence France-Presse), 2011