It was initially reported that the Swede, who joined the Gunners on loan from Russian side Spartak Moscow, could be out for up to three months - which would have effectively ended any hopes of playing in the Premier League.
However, Arsenal's press officer Mark Gonella has quashed such suggestions, stating that the injury to Kallstrom's back is not as serious as first thought.
Speaking to Swedish newspaper Sportbladet, Gonella said: "Kallstrom has hurt his back and he is currently being examined. Arsenal will talk about it tomorrow.
"But I think two or three months is a little excessive. I am not in a position to evaluate it - our team does that now."
And while the Daily Mail implied that he picked up the niggle in his very first Arsenal training session, Aftonbladet reported that the Swede had not even participated with his new team-mates yet, and that the reported minor back issue stems from his Spartak days.
The confusion echos that of Gunners fans who flooded a different Kim Kallstrom with good-luck messages on Twitter after the deal was done.