Reading midfielder Emerse Fae contracted malaria while playing for Ivory Coast at the African Nations Cup, the Premier League club said on Tuesday.
Fae was part of the squad that travelled to Middlesbrough for a league match on Saturday, which Reading won 1-0, but was withdrawn after complaining of feeling ill.
Blood tests in hospital revealed the player, signed from Nantes last year, had the disease.
"It appears that Emerse picked up malaria when he was in Ghana for the African Cup of Nations and it lay dormant for a couple of weeks before coming out over the weekend," club physio Jon Fearn said on Reading's Web site (www.readingfc.premiumtv.co.uk).
"He received prompt treatment and is now under medication. He is recovering well at home and shouldn't be out for too long."
Tottenham Hotspur's Ivory Coast midfielder Didier Zokora also contracted malaria in 2006 while former Newcastle United and Portsmouth player Lomana Lualua, now with Olympiakos, has also had the disease.