The 28-year-old was heavily linked with a loan move away in the transfer window, with former club Newcastle and Arsenal interested in securing his services.
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The competition for places has increased this season after 32-year-old Samuel Eto'o joined on a free transfer, giving manager Jose Mourinho multiple options, including Spaniard Fernando Torres.
And while Romelu Lukaku remains on loan – the Belgian is at Everton this season – Ba is likely to find it tougher to get game time for Chelsea this season.
Despite that, he is remaining positive.
"I told the manager if I stayed I would keep fighting for the club," he said. "Now it's about the next months and years with Chelsea.
"I'm a good professional and always work hard. I will keep doing the same.
"I want to play. It all depends on me and the performance I put in on the pitch. If I don't perform, it will be only my fault."