Clarke later signed a three-month loan deal with Leicester City on 16 August 2007. During the League Cup tie between Nottingham Forest and Leicester on 28 August 2007, Clarke collapsed and suffered a cardiac arrest in the changing rooms at the City Ground causing the match to be abandoned at half-time, with the score at 1–0. It was reported by the BBC that Clarke was being treated in the emergency room at the Queen's Medical Centre in Nottingham. He was said to be 'stable' and would be kept in overnight.