Norwich City manager Dean Smith said there should be a "magic number" of COVID-19 cases in a team for a Premier League fixture to be called off.

Norwich were beaten 2-0 at home on Tuesday by Smith's former team Aston Villa shortly after the league agreed new COVID-19 measures following a record 42 cases among players and staff at clubs over the past week.

Manchester United's match at Brentford was the second game postponed this season due to COVID-19 after Tottenham Hotspur's trip to Brighton & Hove Albion was called off last weekend.

"Our sporting director (Stuart Webber) spoke to the Premier League on guidance when we have symptomatic players around us," Smith told reporters.

"We played Tottenham, they had an outbreak. We played United, they had an outbreak. We wanted guidance over would it be fair on Villa if we had symptomatic players around us?

"I'm not saying all our players are symptomatic and have COVID ... Grant Hanley did his shoulder on Saturday and Ozan Kabak went down, so we have injured players, but we probably need a magic number telling us how many is enough."

Smith said he may not have enough fit players for the West Ham United game on Saturday.

"I'll find out over the next 48 hours from the medical staff about our cases. I've seen new Premier League protocols where we are tested every day. The heat is on, not just across football but across the country."

Norwich also face Arsenal and Crystal Palace this month before meeting Leicester City on New Year's Day.