Sergio Aguero could be fit enough to feature on the bench for Manchester City in their last Champions League group game against Marseille on Wednesday.
Aguero, City's record goalscorer, has played just four times this term after knee surgery in the close season.
The 32-year-old striker has missed the last three matches after suffering discomfort in his knee, with a hamstring injury adding a further complication to his troubled return.
Aguero's last appearance came as a substitute in the Champions League win at Olympiakos on November 25.
"We are going to decide tomorrow. Maybe he is on the bench," Guardiola told reporters on Tuesday.
"Tomorrow we are going to do a training session and see how his reaction is in his body, not just his knee.
"The important thing is the last two, three, four days he was part of the group in the training and his reaction and the niggles he had in the recent past were disappeared."
Aguero's availability means the Argentine might be involved in Saturday's crucial derby against Manchester United as City look to get back in the title race.
"He's working incredibly hard to come back and this is the most important thing," Guardiola said.
"So, of course he needs a little bit more time for the injury and for his physicality, but we are patient so we would love to have him fit and ready."
City are already through to the Champions League last 16 as Group C winners, but Guardiola suggested he would not make a host of changes from the Premier League win against Fulham last weekend.
"We're going to play the game to win the game and I don't rotate the team. I try to put all the players in the best condition for any game and decide the best team for this specific game," Guardiola said.
He said he did not have "one team for one competition and one for another one".
City have become regulars in the knockout stages of the Champions League, but they are yet to win the competition.
They have just one semi-final appearance in 2016, while has Guardiola, a two-time winner as Barcelona manager, has overseen three consecutive quarter-final defeats, including last season's shock loss to Lyon.
Despite those flops, Marseille boss Andre Villas-Boas believes City are good enough to win the Champions League.
"The expectations have been very high for City but there will be nobody with more willingness to win it than Pep at this moment," Villas-Boas said.
"In the Champions League I'm no expert. Pep is the expert, he's won it twice as a manager.
"City have been waiting so long, and the quality they have is second to none, the options they have."
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