Oscar, the younger brother of the pair, is believed to have played his last game for the Demons after five years with the club.
“He will move on,” SEN’s Sam Edmund said on Whateley.
“Opportunities slim for him at Melbourne, both parties agreeing that a trade will almost likely happen.”
The defender has played 81 games for the Demons, but featured on just seven occasions in 2020.
His brother, Tom, is believed to be ready to wait out his contract unless a lucrative offer is made for the out-of-favour swingman.
“If an amazing offer takes place, he’s got two years to run on his deal at Melbourne, then Melbourne will trade him – and the player knows that,” Edmund said.
“But at the moment that doesn’t look like happening.
“It’s a pretty handsome deal this one, he’s got two years to go on it, he’s made some promises about going away and improving his body shape.
“If you’re a betting person you say Tom McDonald stays, unless there is a really big offer.”
Journalist Sam McClure stated that McDonald was “officially up for grabs” on Wednesday.
“Tom McDonald is officially up for grabs,” McClure said.
“He’s got two years left on his deal, the Magpies have reached out and just asked some questions. I’m not sure whether they’ll be the ones he eventually goes to … I don’t think he’ll be at Melbourne next year.”