Kurtley Beale will replace Israel Folau at fullback for the Waratahs against the Rebels.
Beale missed training on Monday and Tuesday with illness but was named at 15 regardless and is set to train with the team on Thursday.
Karmichael Hunt and Adam Ashley-Cooper will team up in the centres for NSW with Cam Clark and Alex Newsome on the wings.
"Three to four days off with tonsillitis and general illness," he said.
"It'll be good to welcome him back.
"With Israel stood down, he'll move into a familiar position at fullback and it's a real opportunity for him to step up in a position that we know he can and really try and own that position for the next nine games."
Gibson said the players were keen to get back on the park after a dramatic week surrounding controversial fullback Israel Folau.
"The off-field events that have swirled around the team, it has been a distraction, but the team on the field are really focused on delivering a performance that we can be proud of and really shows the spirit of this team," he said.
"On-field is a real sanctuary for the players and what I've seen on Monday and Tuesday, is just the release of a lot of energy that's built up and some really good quality stuff."
The Waratahs have a chance to narrow the Rebels' lead at the top of the Australian conference with a win at the SCG.
The Waratahs take on the Rebels on Saturday April 20 at the SCG, kicking off at 7:45pm AEST, LIVE on FOX SPORTS, Kayo and via RUGBY.com.au RADIO. Buy tickets here.
TEAM
Waratahs to face Rebels
1. Harry Johnson-Holmes
2. Damien Fitzpatrick
3. Sekope Kepu
4. Jed Holloway
5. Rob Simmons
6. Jack Dempsey
7. Michael Hooper
8. Michael Wells
9. Jake Gordon
10. Bernard Foley
11. Cam Clark
12. Karmichael Hunt
13. Adam Ashley-Cooper
14. Alex Newsome
15. Kurtley Beale
Reserves
16. Andrew Tuala
17. Rory O'Connor
18. Chris Talakai
19. Tom Staniforth
20. Will Miller
21. Nick Phipps
22. Lalakai Foketi
23. Curtis Rona
