Jones-Buchanan has been Rhinos’ number 11 since the 2007 season, but will wear 20 in his final campaign as he marks two decades since his Leeds debut.
Marquee signing Trent Merrin, who is expected to link up with Leeds next week, will take over number 11.
New boss Dave Furner has rung the changes with England Knights youngsters Ash Handley, Mikolaj Oledzki and Jack Walker all promoted up the squad list.
Walker has been given the coveted number one shirt, with Ashton Golding moving to 21 and Ash Handley will wear five. Oledzki earns a place in the top-20 for the first time at number 19.
Incoming centre Konrad Hurrell takes over number four from Liam Sutcliffe – who drops to 15 – and new arrival Tui Lolohea comes in at six.
Brett Ferres switches from 19 to take the 16 shirt from Anthony Mullally. Dom Crosby – who has signed a three-year contract after a loan spell last season – will wear number 17.
Nathaniel Peteru climbs from 21 to 18 and Rhinos’ fourth new face, Callum McLelland, has been handed number 23.
Cameron Smith moves up from 27 to 22 and Luke Briscoe, a mid-season signing last term, will wear 24.
Youngsters Dan Waite-Pullan (31), Corey Johnson (34) and Tyler Dupree (35) have been allocated a squad number for the first time.
Number 25 has been left open and could be filled by a signing or promotion from the academy ranks. Mullally and Josh Walters, who climbs from 30 to 28, are both understood to have signed a new contract earlier this year, but that has not been confirmed by the club.
Players who have moved on from the 2018 squad are Ryan Hall (number five), Joel Moon (six), Brett Delaney (15), Mitch Garbutt (17), Jimmy Keinhorst (18), Keith Galloway (20), Jordan Lilley (25), Josh Jordan Roberts (29) and Jordan Thompson (37).
Handley described succeeding Hall at number five as a “huge honour”.
He said: “I played a lot at centre last season, but with Konrad Hurrell coming in and Kallum Watkins coming back to full fitness I am happy to do my part for the team on the wing.
“It has been great working with Dave Furner in training and he is really clear what he wants from us.
“We are looking to play an exciting attacking style and that is exciting for all the squad.”
Leeds Rhinos’ 2019 squad numbers: 1 Jack Walker (last season worn by Ashton Golding), 2 Tom Briscoe, 3 Kallum Watkins, 4 Konrad Hurrell (Liam Sutcliffe), 5 Ash Handley (Ryan Hall), 6 Tui Lolohea (Joel Moon), 7 Richie Myler, 8 Adam Cuthbertson, 9 Matt Parcell, 10 Brad Singleton, 11 Trent Merrin (Jamie Jones-Buchanan), 12 Carl Ablett , 13 Stevie Ward, 14 Brad Dwyer, 15 Liam Sutcliffe (Brett Delaney), 16 Brett Ferres (Anthony Mullally), 17 Dom Crosby (Mitch Garbutt), 18 Nathaniel Peteru (Jimmy Keinhorst), 19 Mikolaj Oledzki (Brett Ferres), 20 Jamie Jones-Buchanan (Keith Galloway), 21 Ashton Golding (Nathaniel Peteru), 22 Cameron Smith (Ash Handley), 23 Callum McLellan (Jack Ormondroyd), 24 Luke Briscoe (Jack Walker), 25 vacant (Jordan Lilley), 26 Anthony Mullally (Harry Newman), 27 Jack Ormondroyd (Cameron Smith), 28 Josh Walters (Mikolaj Oledzki), 29 Harry Newman (Josh Jordan-Roberts), 30 Alex Sutcliffe (Josh Walters), 31 Dan Waite-Pullan (Alex Sutcliffe), 32 Thomas Holroyd, 33 Owen Trout, 34 Corey Johnson (Luke Briscoe), 35 Tyler Dupree (not used).