Flanker Tom Cusack and winger Andy Muirhead return to the run-on side for the first time since they split the man-of-the-match honours in Round 3 against the Waratahs.
For the third straight week, Wallabies trio Scott Sio, Folau Fainga'a and Allan Alaalatoa make up the front row, with the impressive young lock pairing of Darcy Swain and Nick Frost completing the tight five.
Cusack is joined by Rob Valetini and Pete Samu in the loose forwards, the latter two starting every game so far in 2020.
The halves see fellow Joe Powell partner with Bayley Kuenzle for the third straight week with Irae Simone and Tevita Kuridrani running the midfield.
Muirhead will be joined in the back three by try-scoring powerhouse Solomone Kata and the electric Tom Banks, who could match up against fellow Wallaby Reece Hodge at fullback.
Canberra boy, Connal McInerney will again be required in the later stages of the match as the replacement hooker, with Harry Lloyd and Tom Ross the other front-row finishers.
Will Miller and Ben Hyne will provide the remaining cover for the forwards.
Former Australian under-20 No 9 Ryan Lonergan will make his first appearance in the new competition as the replacement scrumhalf, with last week's hero Mack Hansen and Len Ikitau rounding out the match-day 23.
McKellar said: "It's great to be able to call on the experience of Tom and Andy and have them slot back into the starting side this week."
"We've got depth and plenty of confidence across the whole squad and to be able to rotate a few bodies after a really physical game against the Reds last week is a positive for us.
"The side has prepared really well ahead of the six-day turnaround and we'll travel up to Leichhardt excited by the challenge of taking on a tough Rebels side tomorrow night."
15 Reece Hodge (co-captain), 14 Andrew Kellaway, 13 Campbell Magnay, 12 Matt Toomua (co-captain), 11 Marika Koroibete, 10 Andrew Deegan, 9 Frank Lomani, 8 Isi Naisarani, 7 Brad Wilkin, 6 Josh Kemeny, 5 Trevor Hosea, 4 Matt Philip, 3 Jermaine Ainsley, 2 Jordan Uelese, 1 Cameron Orr.
Substitutes: 16 Efitusi Ma'afu, 17 Cabous Eloff, 18 Pone Fa'amaluli, 19 Michael Stolberg, 20 Richard Harwick, 21 Rob Leota, 22 James Tuttle, 23 Billy Meakes
15 Tom Banks, 14 Solomone Kata, 13 Tevita Kuridrani, 12 Irae Simone, 11 Andy Muirhead, 10 Bayley Kuenzie, 9 Joe Powell, 8 Pete Samu, 7 Tom Cusack, 6 Rob Valetini, 5 Nick Frost, 4 Darcy Swain, 3 Allan Alaalatoa (captain), 2 Folau Fainga'a, 1 Scott Sio
Substitutes: 16 Connal McInerney, 17 Harry lloyd, 18 Tom Ross, 19 Will Miller, 20 Ben Hyne, 21 Ryan Lonergan, 22 Mack Hansen, 23 Len Ikitau
- TEAMtalk media