Loose-head Jones has been out of action since he suffered the injury during the Ospreys Magners League win over Munster in December, and after coming out of plaster it was clear that the injury had not healed as hoped, as Physio Chris Towers explains:
"Duncan has suffered a few complications with his recovery and the damaged bone in his foot failed to unite during the period he was in plaster. We've been investigating this and seeking expert opinion over the last fortnight, as a result of which Duncan will be having surgery over the next week to hopefully fix the problem.
"At this stage we expect that this will keep him out for around six months."
Meanwhile, tight-head Ross Davies has also been ruled out for the remainder of the campaign following an operation to fix the fractured left fibula and to repair ligament damage in the ankle joint, an injury sustained in the recent training match at St Helen's against Swansea RFC.
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