Cape Town - Borussia Dortmund defender Neven Subotic's proposed move to Middlesbrough is off after a medical assessment revealed a rib injury that will sideline the Serbian for the rest of the year.
Newly-promoted Boro had been expected to sign the defender for around £8m, with Dortmund ready to sell Subotic despite seeing Mats Hummels join rivals FC Bayern München.
However, the 27-year-old's transfer hopes have been scuppered after the injury was discovered during his Boro medical.
"Bad news for Neven Subotic," a BVB statement read. "The investigation of a specialist in England has shown that the Borussia Dortmund player must undergo surgery in the rib area. It is expected that Subotic will be out for the rest of the year."
The Serbia international had missed the back end of the 2015/216 season after he was a diagnosed with thrombosis in his arm.
Subotic has turned out 172 times for Dortmund since arriving from 1. FSV Mainz 05 in 2008, winning the Bundesliga title in 2010 and 2011, and the DFB-Pokal during his time at the club.