England Rugby have released a statement confirming that Mako Vunipola has a small tear of scar tissue which will require approximately 10 days of rehabilitation.
Vunipola sustained the injury as a second-half replacements during Saturday's 57-15 victory over Ireland at Twickenham Stadium.
Ben Moon will join up with the squad as a temporary replacement to train in Treviso.
England next face Italy on 6 September at St James' Park, before flying to Japan on 8 September ahead of the Rugby World Cup. Their first fixture of the tournament is against Tonga on 22 September.