
Carrick suffered the injury late in United's Champions League win over Roma on Tuesday and X-rays after the game showed he had suffered a fracture.
The 26-year-old will miss England's two Euro 2008 qualifying games against Estonia and Russia later this month and leaves United with only one recognised central midfielder in Paul Scholes.
Owen Hargreaves is out for up to four weeks with a knee injury while Darren Fletcher also has a knee problem.
DPA