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.
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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.