Torbjorn Heggem has completed his move from West Bromwich Albion to Serie A club Bologna for a fee in the region of £10m.
The Norway defender joined the Baggies from Swedish club IF Brommapojkarna last summer and missed only one game in the Championship during the 2024-25 season.
A sell-on clause has been included in the deal.
The transfer means Albion have recouped a significant profit within 12 months on the 26-year-old.
Heggem was named the Baggies' player of the season by supporters and team-mates last season.
He has seven caps for Norway having made his debut in 2024.