The Antalyaspor boss, who worked alongside Jose Mourinho for six years, was taken to the hospital on Wednesday and is unlikely to be in the dugout against Fenerbahce.
Antalyaspor coach Jose Morais remains under observation in hospital having suffered a suspected brain haemorrhage.
Morais, who worked alongside Jose Mourinho at Porto, Chelsea, Inter and Real Madrid, was admitted to the hospital on Wednesday with severe headaches and has been kept in overnight.
The 50-year-old left Chelsea along with Mourinho in January following his sacking and was linked with the vacant manager’s position at Swansea before joining the Turkish Super Lig club in January.