​Rumours linking Branislav Ivanovic with a surprise move to Barcelona continue to gather pace, with the Serbian defender refusing to rule out a move to the Catalan club.

Ivanovic's name was first mentioned in connection with Barcelona over a month ago and the rumours have resurfaced as concerns grow over the long-term fitness of Samuel Umtiti, who has been struggling with a recurring knee injury.

The former ​Chelsea defender insists he is happy at Zenit St. Petersburg but stopped short of committing his future to the club, where he is out of contract at the end of the season.

"I am pleased with everything at Zenit," he said on Sunday, quoted by Zenit's official website. "But in football, you never know what will happen tomorrow.

"Now I'm giving everything to Zenit and preparing for the next game."

Unless Ivanovic signs a new contract at the Krestovsky Stadium before the end of 2018, he will be allowed to talk to potential suitors from January onwards. Given his age, Ivanovic would only be a short term option for ​Barcelona before they can pursue more illustrious targets next summer.

In the long term, Barcelona want Matthijs de Ligt to be their new star centre back, but Ajax will not enter into negotiations midway through the season.

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Ernesto Valverde's side have not kept a clean sheet in the league since August and only five teams in La Liga have conceded more goals.

By contrast, Ivanovic's Zenit kept their fifth consecutive clean sheet in the Russian Premier League on Sunday as they beat Rostov 2-0 to remain five points clear at the top.