Nigel Pearson revealed Tomas Kalas has been playing through the pain barrier for two seasons and won't rush him back into action, even after the international break.
The centre-back has missed the last two matches with a groin issue with the City manager previously laying blame to the amount of football he has played both for club and country in the last couple of years.
Kalas, 28, was initially a doubt to face Blackburn last weekend before Czech Republic opted not to call him up for their international fixtures next week - suggesting his injury is more serious than first reported.
