The Belgian joined the Catalan giants in 2014 from Arsenal but has endured a frustrating three years in Catalonia.
Injuries have limited the 31-year-old to just 21 appearances in all competitions for Barca. Vermaelen was shipped out on loan to Roma last season where he endured another frustrating campaign, making just four starts in Serie A.
The defender still has two years left on his contract at the Nou Camp but Ernesto Valverde’s side are prepared to let the player leave this summer.
Tony Pulis has been on the lookout for defensive reinforcements this summer and has been linked with a move for Middlesbrough’s Ben Gibson, though Vermaelen offers a more experienced and cheaper alternative.