Roma dependent on Totti for derby
The striker has missed much of the season due to the after-effects of a knee operation and his performances when he has played have been below his usual high standards.
His problems have had a big role in the troubles of last year's runners-up, who have eight points from 10 games and are one point above the Serie A relegation zone and 14 behind fourth-placed Lazio.
However, he played in last week's morale-boosting 3-1 Champions League win over Chelsea and scored in Saturday's 1-1 draw at Bologna, raising hopes the real Totti is returning.
"Totti is back and this could be the turning point," former Liverpool full back John Arne Riise was quoted as saying by Corriere dello Sport.
"The effect he has on the team reminds me of (Steven) Gerrard's at Liverpool. Totti is a leader and a great player and we need him for the future."
The sound form of Lazio, who are two points behind leaders Inter Milan, is almost as much of a surprise as Roma's lowly status in the standings.
It is based on an attacking approach that has made them Serie A's most prolific side, with Macedonia forward Goran Pandev and new Argentine signing Mauro Zarate contributing five and seven goals respectively.
Lazio coach Delio Rossi is expected to field an offensive trident of Pandev, Zarate and captain Tommaso Rocchi, who recovered from injury to score twice in last weekend's 3-0 win over Siena.
"They are doing very well up front, but we fear no one," Roma defender Christian Panucci said.
"We need a positive result now more than ever. There was a sign of improvement against Chelsea. We are in treatment. Only when the results come can we say the treatment is over."
Roma's Daniele De Rossi is a doubt after hurting his hand in a fall in training on Thursday while fellow midfielder David Pizarro is suspended.
Champions Inter visit Palermo on Saturday, while second-placed AC Milan, who are one point behind them with 23, entertain Chievo Verona on Sunday.
Third-placed Napoli, who also have 23 points, visit Atalanta in Bergamo on Sunday.
Juventus can join Inter at the top if they beat Genoa at home on Thursday, a match being played ahead of the rest of the Serie A schedule because the Italian national rugby team take on Argentina in Turin on Saturday.