The Blues left-back twisted his ankle in the first half of the 3-1 win over the Magpies at St. Andrew's and had to be withdrawn at half-time.
Williams is now expected to be sidelined for up to three weeks with this the latest in a series of injuries sustained in the last twelve months.
The 23-year-old Blues left-back fell over a pot-hole on a practice pitch towards the end of last year while on a season long loan deal at QPR and ruptured his anterior fibula ligament forcing him out for about three months of the season.
