Sergio Aguero, David Silva and Samir Nasri were all sent home with stomach bugs before the ‘City Live’ season launch event took place on Wednesday evening.
Aguero had been due to collect the club’s 2014/15 player of the year award in front of 3,000 fans at the gathering in central Manchester.
All three players are expected to recover in time for the trip to The Hawthorns but the circumstances are not ideal for manager Manuel Pellegrini.
Aguero, City’s top scorer last season with 32 goals in all competitions, sent a video message saying: “Sorry I can’t be there, I don’t feel well. I will be back soon.”