Newcastle boss Eddie Howe said his side are "dangerously close" to not being able to field a team for their Premier League game at Everton on 30 December.
Before the 1-1 draw with Manchester United on Monday, Howe said his squad was "stretched" and had a "mixture of injuries and Covid-19 cases".
Forwards Callum Wilson and Allan Saint-Maximin both then suffered injures during the game at St James' Park.
Howe fears Wilson could be facing "months" on the sidelines.
Newcastle are 19th in the table, two points behind 17th-placed Watford.
"Callum's injury looks severe, weeks maybe months," Howe told BBC Radio 5 Live.