England legend Ray Clemence was taken to hospital on the eve of the Three Lions' victory over European and World champions Spain on Saturday.
The 63-year-old, officially titled Head of National Teams, missed Capello's men secure a 1-0 win over Spain at Wembley over the weekend.
The Football Association has confirmed that the former Liverpool goalkeeper, who won 61 caps for the national team, had been feeling unwell.
Clemence was forced to step down as goalkeeping coach for the Three Lions in 2005 after being diagnosed with prostate cancer, but returned after his health improved.
Clemence is expected to miss England's international friendly against Sweden tomorrow.