And with less than a month to go until the kick-off of the tenth anniversary season of the Heineken Cup Blues coach Dai Young is frustrated at the possibility of losing the player at such an important point in the season.
"The doctors can't pin-point the virus so they can't give a recovery period," he told BBC Sport.
"It's a huge frustration for Nicky and for us. He wanted a big start to the season to keep the No 10 jersey for us and for Wales."
Robinson has already missed the opening four games of the Arms Park outfit's domestic season thanks to the illness with Nick Macleod and youngster Lee Thomas having to share the No 10 duties.
But coach Young will be desperate to see Robinson recover to have the fly-half's place-kicking and running abilities back at his disposal when the Blues travel to Ravenhill on October 22 for their tricky opener with former champions Ulster Rugby.