Hasleby, who recently retired after 208 games in 11 seasons for Fremantle, handed over his cherished jumper number to Pitt on Monday.
The four-time Ross Glendinning Medallist, who will play for WAFL club South Fremantle in 2011, said he was excited to pass on his number and finalise his AFL retirement.
"A lot of sweat, blood and tears have gone into trying to do my best in the number four and it's with great pleasure that I hand it over to Jayden Pitt," Hasleby said from Fremantle Oval on Monday.
"He's a quality kid with a good work ethic and I'm sure he’ll do the number proud."
Pitt, who was taken by Fremantle with pick No.20 at the 2010 NAB AFL Draft, will be the third Fremantle player to wear number four, following Hasleby and half-forward Andrew Wills.
"It's a huge honour to take over the number four, with Paul being a legend of the club and a 200-game player," the 18-year-old said.
"I wasn't expecting it, but I'm more than happy to take over."
Impressive half-forward Nat Fyfe has moved from No.13 to the No.7 jumper vacated by the retired Dean Solomon, while former Collingwood forward John Anthony will wear No.22 at his new club.
Ruck recruit Jon Griffin will wear No.12, while fellow newcomers Viv Michie (No.20), Josh Mellington (No.25), Peter Faulks (No.28) and Tendai Mzungu (No.13) were also allocated their numbers on Monday.
Rookies Nick Lower (No.34) and Gavin Roberts (No.42) rounded out the club's jumper allocations for the 2011 season.
