Borussia Dortmund's Neven Subotic has been allowed to conduct transfer negotiations over a move, with Sunderland linked to the centre-half earlier this summer.
Bundesliga outfit Dortmund tweeted today that Subotic had been given permission to hold talks with a "potential new club" although they didn't reveal the identity of the suitor.
Subotic has been linked with a move to Sunderland, but Liverpool, Arsenal, Stoke and Cologne have also been credited with a strong interest in the 27-year-old.
Sunderland are keen to bring in a new centre-half this summer, but the Black Cats' main priority is thought to be another frontman, with their hopes of landing West Ham's Diafra Sakho continuing to be frustrated.
West Ham want to sign a new striker before sanctioning Sakho's departure, but their attempts to land a high-profile name have been hampered so far this summer.
Carlos Tevez is the latest Hammers target to fall through after the Argentine demanded a £250,000 a week pay packet to rejoin his former club.
Meanwhile, the Sunderland squad flew to their pre-season training camp in Austria today with speculation continuing over the future of manager Sam Allardyce.
The Sun reports today that bookies favourite Allardyce has held provisional talks with the FA over the England job, although there are reports elsewhere that Arsenal boss Arsene Wenger is still in contention.