Argentinian back rower Guido Volpi is leaving the Ospreys at the end of the season.
The 25-year-old arrived in Swansea in 2018 but has been on loan at Doncaster Knights.
Now he is to join the Knights on a two-year deal.
The South American has proven a popular member of the Ospreys squad and signed a two-year contract with the region last summer.
In total, he made seven appearances for the Welsh team after pitching up from Narbonne.
A former Argentina U18s player, the No. 8 has had two loan spells with Doncaster, with the English club sufficiently impressed to want to make his stay more permanent.
