The Belgium international has experienced a torrid run with injuries since moving to Camp Nou from Arsenal in 2014.
Vermaelen was sent out on loan to Roma last season, but experienced the same bad luck with injuries.
The 31-year old played in 110 Premier League games for the Gunners.
And according to Sky Sports, the Baggies and Crystal Palace are assessing whether Vermaelen can hold off his injury concerns and return to the Premier League.
Source: Tribal football