Law sat out his first league game of the season at the weekend after hurting his knee in the midweek match with Milton Keynes Dons.
It is believed the injury is only a minor one, however, and McCall hasn't ruled out the midfielder being back in contention by the time the Bantams make the trip to Coventry City this Saturday.
McCall said: "He tweaked his knee on Tuesday night (vs Milton Keynes Dons).
"An injury like that is normally seven-to-ten days, so we hope that he can back training on Thursday and then available for Saturday (vs Coventry).