West Ham United's co-chairman David Gold has been taken into hospital with pneumonia.
The 76-year-old, who spent several days in hospital in 2011 with septicaemia, is currently on a course of antibiotics.
"I think he's learnt a very harsh lesson - not to go to football with bronchitis, he now has pneumonia. He is being assessed," his daughter Jacqueline wrote on Twitter.
Along with David Sullivan, Gold gained control of Premier League side West Ham in 2010.