Argentine back-row Guido Volpi will leave Ospreys at the end of this season to join English Championship side Doncaster Knights on a two-year deal.
The 25-year-old arrived in Doncaster on loan in January 2020 and that agreement was extended for the 2021 campaign.
Welsh winger Kyle Evans, 29, has also agreed a new deal, signing a one-year extension having joined from Merthyr RFC in the summer of 2019.
"I'm happy to sign Guido on a permanent basis," Knights boss Steve Boden said.
"He is a big character within the squad and his game has developed leaps and bounds this season, but what's really exciting is that we feel there is a huge amount of growth in his game to unlock."
Volpi arrived at the Liberty Stadium from Narbonne in France at the start of the 2018-19 season and played seven times for Ospreys.