Zenit said the Serbia captain, who played for Lokomotiv Moscow before joining current Premier League leaders Chelsea in 2008, had the option of extending his contract for another year.
"I had a very big hope to come back to Russia and to play here. I am motivated and I think that I can play for many more seasons at the top level," he told Zenit's website (en.fc-zenit.ru)
The 32-year-old, who won two Premier League titles and the Champions League with Chelsea, would have been out of contract with the Londoners at the end of the season.
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"I am happy just to play. I am happy in (the) centre or on the right (of defence). That’s probably a question for the manager but I am happy to play in any position," he said.
(Reporting by Alan Baldwin, editing by Ken Ferris)
