Sunderland face a battle to convince Pavel Pogrebnyak to leave Stuttgart.
The striker's agent, Oleg Artemov, confirmed their interest yesterday.
But he added: "Nothing has changed. Pavel has one more year left on his contract. Usually in this case the club would begin talks about a renewal or a sale, but Stuttgart keep silent.
"I can imagine a situation where Pavel sticks with Stuttgart until the end of his contract and moves to another team as a free agent. Any option is possible."
