The influential 28-year-old has only just returned to training after being forced off at half-time during Spain's 2-1 win against England in last month's Euro 2024 final.
While England trio Phil Foden, John Stones and Kyle Walker hope to feature at Stamford Bridge after their post-Euros break, Rodri has not been cleared to return to action.
Asked on Friday if Rodri could be involved against Chelsea, Guardiola told reporters: "No chance.
"He is in training. I don't know, I haven't seen him yet. He feels good. We'll have to see how he feels after training."
Rodri's absence is an early blow to City's bid to win a fifth successive Premier League title.
City would love to make a strong start to their title defence in west London, but Guardiola admitted fitness issues could hamper them on the opening weekend.
Foden, Stones and Walker are not fully fit after only returning to training in midweek following their holidays.
"I'm pretty sure they won't be ready for 90 minutes, maybe yes, maybe 15 minutes," Guardiola said.
"The important thing is everybody is back and except for Oscar (Bobb) the rest are OK."
Bobb will have surgery on Friday to repair a fractured bone in his leg following a non-contact training ground incident on Wednesday.
Guardiola expects the young Norway winger to be sidelined for up to four months.
"Unfortunately, he had a big impact and got injured," Guardiola said. "He is having surgery this afternoon.
"Hopefully, it will go well and he will be back in three or four months. We are so sad for him."
Bobb's setback follows the recent departure of Argentina forward Julian Alvarez to Atletico Madrid and Guardiola said he could be forced into the transfer market for replacements.
"Maybe or maybe not, we will see," the Spaniard said. "I'm really pleased with the squad I have, we will see. I'm set.
"We will see what happens in the market. We can continue to January in that way or maybe we will add some players."
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