This freshly-inked contract that is set to expire at the completion of the 2025 season is an enormous show of faith in the redheaded Redleg who proved his worth across 19-games in 2021.
This extension was tabled to and signed by Petty despite already remaining contracted to the AAMI Park club until the end of 2022.
While the South Australian had struggled to gain regular access to Simon Goodwin's senior side following his selection with the 37th pick of the 2017 draft, a season-ending knee injury to fellow backman Adam Tomlinson in Round 7 provided Petty with an unimpeded passage to premiership glory.
The 197cm prospect rounded out his third campaign with the club by producing career-best returns across every statistic and earning immortality as one of the Demons' 23 drought-breakers.
Speaking publically via an official statement released on Monday afternoon, Melbourne's list manager, Tim Lamb, claimed that the Norwood product would remain a key pillar in defence for many years to come.
“We all saw the rate of his development this year and we are really excited to see how far he can take his game,” he told melbournefc.com.au.
“Harrison is a crucial piece of our future and we anticipate him being a key member of our defensive unit for many years to come.
“He is a terrific teammate who is highly respected by everyone and we look forward to watching him continue to develop over the coming seasons.
“To have Harrison commit to the club is brilliant, his performances particularly throughout the finals series were exceptional."
Though Tomlinson is predicted to return to Goodwin's starting-22 at some stage next season, Petty's performances produced throughout 2021 are likely to give his head coach selection headaches if they continue to be replicated.
The squad member for the latest 22under22 team has played 30-games since commencing calling Victoria home.