Petracca, pick No.2 in the 2014 NAB AFL Draft has opted for the No.26 jumper, most recently worn by delisted midfielder Daniel Nicholson.
Brayshaw has been handed the No.10 guernsey, previously worn by Shannon Byrnes - who is now a development coach at the club - which he wore during his time with the Sandringham Dragons in the TAC Cup.
Draftees' mental and physical shock after first training session
Oscar McDonald will wear the No.28, three locker numbers away from older brother Tom (No.25).
South Australian draftee Alex Neal-Bullen will pull on the No.30 guernsey next year, while father-son recruit Billy Stretch has been handed the No.15.
Rookies Aaron Vandenberg (No.37) and Mitchell White (No.41) have also been allocated their jumper numbers.
As the Demons previously announced, ruckman Max Gawn has inherited Jim Stynes' prestigious No.11 guernsey.
Recruits Heritier Lumumba (No.8), Sam Frost (No.17), Ben Newton (No.19) and Jeff Garlett (No.36) have also been handed their new numbers.
2015 Melbourne numbers
1 – Jesse Hogan
2 – Nathan Jones
3 – Christian Salem
4 – Jack Watts
5 – Jimmy Toumpas
6 – Chris Dawes
7 – Jack Viney
8 – Heritier Lumumba
9 – Jack Trengove
10 – Angus Brayshaw
11 – Max Gawn
12 – Dom Tyson
13 – Jordie McKenzie
14 – Lynden Dunn
15 – Billy Stretch
16 – Dean Kent
17 – Sam Frost
18 – Daniel Cross
19 – Ben Newton
20 – Colin Garland
21 – Cameron Pedersen
22 – Viv Michie
23 – Bernie Vince
24 – Jay Kennedy-Harris
25 – Tom McDonald
26 – Christian Petracca
27 – Aidan Riley
28 – Oscar McDonald
29 – Jayden Hunt
30 – Alex Neal-Bullen
31 – Jack Grimes
32 – N/A
33 – N/A
34 – N/A
35 – N/A
36 – Jeff Garlett
37 – Aaron Vandenberg
38 – Jeremy Howe
39 – Neville Jetta
40 – Mark Jamar
41 – Mitchell White
42 – Jake Spencer
43 – James Harmes
44 – Rohan Bail
45 – Matt Jones
46 – Dean Terlich
47 – Max King
48 – Jack Fitzpatrick