Westwood was injured towards the end of the first half of the Premier League match at Villa Park when he was fouled by Leicester forward Jamie Vardy.
The 24-year-old, who set up Villa's equaliser, had a scan on Monday.
"He wouldn't go down unless it was serious," said Villa manager Paul Lambert immediately after the match.
Before being stretchered off, Westwood provided the assist for Ciaran Clark to level after Leonardo Ulloa had put the Foxes ahead.
Alan Hutton's first Villa goal then secured three points for the home side that, coming on the back of the 1-0 victory away to Crystal Palace on Tuesday, moved Lambert's side up to 11th in the table.