The England midfielder made his Major League Soccer debut on Thursday when he came on for the final 18 minutes of his side's 1-0 defeat by DC United.
But he aggravated the injury and was not even on the bench on Sunday.
"I'm not sure about my ankle. It flared up again after the DC United game," said the 32-year-old.
Meanwhile, Galaxy captain Landon Donovan is relishing the time when the former England skipper is fit to take a regular place in the side.
"I want him on the field all the time because he makes us better," stated Donovan.