COLLINGWOOD father-son draftee Callum Brown is battling glandular fever and will be sidelined from pre-season training for at least "a few weeks".
Brown, the son of 1990 premiership star Gavin, reported a sore throat last week and struggled through training.
"He was subsequently diagnosed over the weekend and has returned a verdict of glandular fever," general manager of football Geoff Walsh told the club's website.
"He will be away from the club at least for the whole week and then once his bloods have returned and he’s feeling back to normal and OK, the medical team will make an assessment from next week onwards.
"It will obviously take him out of the mainstream program for a few weeks. We will just see how he progresses from there."
Brown, a 177cm midfielder-forward taken with pick 35 in last year's NAB AFL Draft, is not the first Magpie to suffer the illness.
Skipper Scott Pendlebury battled the condition in 2006, while Tim Broomhead suffered glandular fever in 2013.
"It’s a bit of a blow for (Brown) because he has been training well and looking good for a young fella in his first pre-season," Walsh said.