Roberts is unlikely to be available for Rovers' trip to Manchester United in the Barclays Premier League after showing symptoms of the virus.
Manager Sam Allardyce, who has suffered with the illness himself in the last few days, said that he and most of his squad had recovered after an outbreak in the camp last week but confirmed that Roberts was being seen by a doctor.
"I'm okay now - I think we've only Jason Roberts," Allardyce said.
"There was another player suffering with it earlier in the week and Jason looks like it now, so we've left him at home and sent the doctor out to see him.
"The symptoms look very much like the general swine flu symptoms, so we will obviously go and get a full check on him."