A scan carried out on Tuesday identified 'a crack in a bone in his left foot' and Zebo will continue to wear the medical boot he was issued with post-match in Edinburgh for the next four weeks.
A spell of up to ten weeks on the sidelines rules the 2013 Lions player out of Munster's next three pool games in the Heineken Cup - this weekend's home date with Gloucester and the December double header against Perpignan.
Zebo is also set to miss Ireland's entire GUINNESS Series next month - Samoa, Australia and New Zealand are the visitors to the Aviva Stadium.
The 22-year-old had been part of the 42-man squad that trained under new Ireland head coach Joe Schmidt in Carton House last month.
He made his Ireland senior debut on the wing against the All Blacks during the 2012 summer tour, and followed up with two starts at full-back in last November's GUINNESS Series against South Africa and Argentina.
The Cork youngster scored his first international try against the Pumas and added his second in a memorable Six Nations debut against Wales last February.
Zebo fractured the fifth metatarsal in his right foot against England and missed the rest of the Championship, before returning to win his sixth Ireland cap against the USA in June and earning a late call-up to the British & Irish Lions tour.