Stoke striker Tuncay is currently having a medical at German giants Wolfsburg.
The two clubs have yet to agree a fee, with a £4m bid from Wolfsburg on the table, but the deal seems to rest on whether the Potters can get a replacement in before the deadline passes.
Tuncay joined from Middlesbrough for £5m in August 2009 but has failed to nail down a regular spot in the City first team, scoring eight goals in 55 games, but just 26 starts.
If the deal goes through the Turkish international captain will again link up with former England and Middlesbrough manager Steve McClaren, who signed the forward from Fenerbahce when in charge at the Riverside Stadium.