The Tottenham goalkeeper picked up a knock in Sunday's win over Manchester City and will sit out the next two games, with usual deputy Michel Vorm expected to play instead.
Tottenham will be without Hugo Lloris for its Europa League clash with Fiorentina on Thursday after he suffered a shoulder injury against Manchester City.
The France international suffered the injury in the closing minutes of Sunday's Premier League fixture as Spurs moved within two points of leader Leicester City.
The issue will see him sit out the trip to Florence, while he could also be absent for Spurs' FA Cup fifth-round encounter with Crystal Palace three days later
"Bad news," boss Mauricio Pochettino told the club's official website.