Widespread media reports suggest Hugo Lloris is set to be ruled out for between six to eight weeks.
The Tottenham Hotspur goalkeeper is believed to have suffered a knee injury during Sunday's 1-0 win over Manchester City.
Such a timeframe of absence would result in the France international missing up to six Premier League matches and represent a huge blow to the club's top-four hopes.
Antonio Conte's side lie fifth in the table, a point behind Newcastle United having played a match more.
Lloris, 36, would also miss both legs of hisside's last-16 UEFA Champions League tie against AC Milan, with the first leg set to take place on 14 February.
Lloris's likely deputy, Fraser Forster, has started one Premier League match since joining Spurs last summer from Southampton, a 2-2 draw at Brentford in December.
Spurs are already without defender Cristian Romero for Saturday's trip to Leicester City following his sending-off for two bookable offences in the victory over Man City.