Redpath sustained the damage to the anterior cruciate ligament in his right knee in the closing moments of the May 14 showdown at the Recreation Ground and is to undergo surgery on Wednesday.
A recovery time of six to nine months rules him out of Scotland's summer Tests against Romania and Georgia and also their entire autumn campaign, with a December return for Bath the most optimistic outlook for his comeback.
A Bath statement read: "The rehab team will work with the 21-year-old after his surgery to allow him to be back to his best as soon as possible.
"Everyone at Bath wish Cameron every step of the way and wish him a speedy recovery."
It is a savage blow for Redpath, who impressed on his Test debut against England in February to the extent that he was seen as a bolter for the British and Irish Lions tour to South Africa this summer.
However, he also suffered a neck injury in that match and missed the rest of the Six Nations.
Redpath was selected in England's squad for their 2018 tour to South Africa only to suffer an ACL injury to his left knee, forcing him to withdraw from Eddie Jones' squad. He later pledged allegiance to Scotland.