Antonio Harris moves from prop to hooker and Sam Smith moves from flanker to number eight.
Louis Chaudron has been named on the bench so number seven Andrew Boyce will captain the side.
Hewitt's side will be hoping it's third time lucky after defeats to Newcastle Falcons and Leicester Tigers.
Gloucester will be captained by England 18s squad member Lewis Ludlow as they look to build on a strong start in the Academies North League which saw them beat Northampton Saints in their first game.
The game kicks-off at 11am and fans can watch for free.
Warriors Under 18s team to face Gloucester
1 Joe Wrafter; Worcester 6th Form College
2 Antonio Harris; Worcester 6th Form College
3 Dave Whiting; Worcester 6th Form College
4 Matt Perks; Dudley Kingswinford RFC
5 Scott Makepiece; Worcester 6th Form College
6 Huw Harris; Old Swinford Hospital School
7 Andrew Boyce (c) - Kings Worcester
8 Sam Smith; Old Swinford Hospital School
9 Ben Williams; Worcester 6th Form College
10 Elliott Davies; Bromsgrove School
11 Colin Dickson; Ellesmere College
12 James Young; Bromsgrove School
13 Dan Hope; Worcester 6th Form College
14 David Sarafini; Kings Worcester
15 John Hughes; RGS Worcester
16 Callum Young; Bromsgrove School
17 Adam Johns; Kings Worcester
18 Lewis Hodnett; Shrewsbury School
19 Will Elt; Kings Worcester
20 Louis Chaudron; Ellesmere College
21 Josh Feek; Old Swinford Hospital School
22 Jake Pratley; Worcester 6th Form College
23 Luke White; Tarporley High School