Sane is already back in light training but, despite the second leg against Basel being just short of a month away, Guardiola is planning to be without the 22-year-old for both fixtures.
"He is much better but I don't think he will be back for the Champions League. He's just running in training," he told reporters at his weekly presser ahead of Saturday's league meeting with Leicester City.
Guardiola also explained the reasons behind giving his players a four-day rest this week, adding: "We have had a lot of games since August and just one midweek off, we needed it. We made three good training sessions and then we come back.
"We love to play football but when you play every three days, sometimes a break is good for everybody because you come back strong. We have Saturday, three days later Champions League, then five days, and then five days for the League Cup final. We will see day by day how the players feel.
"Some players are not fit. Others will come back. I would like to rest Sergio Aguero but he's the only striker we have. He is making a huge effort and doing really well. But Gabriel Jesus is coming back soon - maybe 10 days, two weeks."
Man City have won each of their last 12 league matches at the Etihad Stadium.