The Dutch stopper hurt himself when trying to save Carlos Tevez's winning goal in City's 1-0 victory but despite admitting that he is "desperate" to return, he has insisted that he cannot rush his recovery.
Vorm said: "My rehabilitation is going well. I couldn't walk normally last week, but now I'm okay and the bruise is slowly going.
"I've been doing a lot of work in the gym to keep my strength up and the blood flowing.
"I'm determined to heal quickly and strongly. I'm desperate to come back, but I know I can't rush it. I'd rather be one week later than a week too early and it goes again."
The 29-year-old has made 46 appearances for Swansea since joining the club from Utrecht in 2011.