The 157-game former Melbourne and Carlton player has spent the past two seasons with Doncaster East, where he helped the club secure two premierships and promotion from division two to the Premier Division.
McLean, 33, comes to the club via a connection with United ruckman and assistant coach Shane Neaves — but will not be the only new Demon this season.
Northern Blues-listed VFL talent Cam Wild has switched from Shepparton to Shepparton United, where he will look to continue to build his quickly growing reputation.
Wild, who finished runner-up in the Murray Bushrangers’ best-and-fairest last season, only played one senior game for the Bears but it was certainly one to remember, turning in a best-on-ground display in an elimination final win against Tatura.
Nagambie duo Blake and Nathan Fothergill will also join the Demons fresh from Kyabram District League premiership success, while Waaia's Mitch Cleeland is another to make the jump to United after starring in defence for the Bombers in recent seasons.
But elsewhere in the GVL, Shepparton's player exodus has continued with 2018 premiership duo Joel Brett and Liam Duguid cleared to Bendigo Football League.
The pair has joined Golden Square, meaning 10 of the 2018 premiership 21 have now departed Deakin Reserve, while players from last season including Tom Thorsen, Tyler Bell, Hugo Ingham and the aforementioned Wild have also left.
Mansfield will be without important defender Lachie Christopher, after he and his partner, Eagles A-grade netball coach Emily Hutchins, signed with Ballarat league side Bacchus Marsh.
Tatura has also lost a gun, with Box Hill VFL-listed Matt Shannon departing for Eastern league club Balwyn after an impressive season with the Bulldogs.
And Mooroopna has also lost one of its best players, with former Frankston VFL talent Kyle Gray headed for Geelong league side St Joseph's.
● In the Kyabram District League, Violet Town has continued to add to its arsenal with the acquisition of former Euroa player Harry Sleigh.
Sleigh, who has played 29 senior games for the Magpies, joins the side from Old Geelong, but has also played in AFL Queensland and AFL Sydney.
Jack McPherson is also heading to the Town from Old Geelong.
And Avenel has kept raiding Seymour's GVL reserves premiership side with Tom Martin and Jordan Zuccala joining Max Jones in moving to the Swans.
The Swans have also signed half-back Ryland Head from Maryborough Castlemaine league club Trentham District.