MELBOURNE rookie Leigh Williams is recovering in hospital after he was diagnosed with a viral infection of the brain on Saturday night.

The 21-year-old was rushed to hospital via ambulance after becoming seriously ill on Saturday evening and was admitted to the intensive care unit at Box Hill Hospital.

After being diagnosed with viral encephalitis, Williams was placed in an induced coma.

Over the next two days he was treated with antiviral medication and was conscious on Monday morning.

The young Demon is now expected to make a full recovery, but will remain in hospital over the next two weeks to receive further treatment.

The health scare was a major shock to the Demons and those connected to Williams, who is yet to play a senior game with Melbourne after joining the club this year.

“This is obviously deeply concerning for Leigh, his family and the club," said Melbourne football manager Josh Mahoney.

"Our focus is to ensure Leigh’s health continues to improve, as it has over the past 48 hours and that he makes a full recovery. Clearly returning to football is secondary to Leigh’s health and we certainly won’t be rushing anything in that regard.”

The Demons used pick No.59 in the 2012 rookie draft to put the 193cm Williams on its rookie list this season.

The marking forward had played just two games with Casey Scorpions in the VFL before being struck down with the virus.

Williams had trained during the pre-season with the Demons after kicking 88 goals for Norwood in Melbourne's Eastern Football League in 2011.