The Blues said it would trade selection No.11 in November's NAB AFL Draft for the 23-year-old, who has played 94 games since making his debut in 2004.
Carlton coach Brett Ratten said the Blues were looking forward to McLean's arrival at Visy Park.
"While not official until the exchange period, it is certainly exciting to know we will be adding such a quality midfielder to our playing group in 2010," Ratten said.
"At just 23 years of age, Brock is still a young player and has great experience that will assist our young playing group.
"He is a fantastic in-close player and I am sure the likes of Chris Judd, Marc Murphy, Bryce Gibbs, Kade Simpson will benefit from his ability to get the ball out to them.
"It is a great reflection on where this club is heading to know that such a quality young player is keen to join Carlton."
Melbourne announced on Wednesday night that McLean had requested a trade and had reached an in-principle agreement with the Blues.
The deal is subject to a medical screening and the finalisation of paper work during trade week, which will commence on October 5.
Carlton CEO Greg Swann said McLean's decision to request Visy Park as his new home indicated the club was pointed in the right direction.
"Brock is a quality midfielder, and importantly, he plays an inside game and will provide great assistance to our running players," he said.
"The fact he was keen to join Carlton is a positive reflection on our club and the exciting outlook that many see for Carlton."
McLean will join former Melbourne teammate Chris Johnson who was picked up by the Blues in last year's NAB AFL Pre-season Draft.
