Lucas Joao's 11th league goal rescued a point in London following Jed Wallace's stunning free-kick on the stroke of half-time.
The visitors also picked up a point in midweek with a 0-0 draw against fellow play-off outfit Watford.
With John Swift and Andy Yiadom remaining out, academy graduate Tom Holmes is expected to retain his place at right-back.
Fellow academy star Michael Olise set up Joao's equaliser against the Lions despite starting on the bench, and so may receive a call up to start.
Former Royal Adrian Mariappa may make his Robins debut in place of the injured Tomas Kalas.
Rafael; Holmes, Morrison, Moore, Richards; Rinomhota, Laurent; Meite, Olise, Ejaria, Joao
Bentley; Vyner, Moore, Mariappa; Hunt, Paterson, Nagy, O'Dowda, Dasilva; Semenyo, Wells
Ones to watch
Joao remains in the form of his career, scoring more goals this season so far than he managed in the last three years combined.
19-year-old Olise is also producing the best output of his relatively short career, with six goal contributions.
For Dean Holden's side it is wide-man Jamie Paterson, who has five goal contributions so far this season.
The travelling side completed the double over the hosts last season, with a 1-0 win for Bristol City in both matches.
Paterson's goal was the difference in January, the last meeting between the two sides.
Veljko Paunovic insists his side is ready for war against Bristol City, determined to gain the sides first win in five matches.
"As we always say – next game. We will recover, replenish, prepare and compete.
“We will be ready for that game, but we know we can expect a hard opponent. But we’re keen, and we’re happy.
“It will be an interesting game and we have already been preparing for them. It’s another hard opponent, another final. Another battle, another war.
“They’re organised, and they’re good on the ball. It’s a team that know how they play and they have good spirit, and a tough mentality. They never give up.
“It will be a good clash – in certain ways, a clash of two similar teams. In terms of the way we started the season and where we are in the standings."
Former assistant Holden is calling for defensive stability and clean sheets as they look to continue marching up the table.
“Clean sheets are a big part of a successful season.
"It keeps the run going, the spirit is good and we roll on to Saturday against Reading."
How to watch
The game is live on Sky Sports, and so is unavailable to purchase on iFollow.