Full back Kyle Walker came off early during Wednesday’s Champions League win over Club Brugge as a precaution with a foot problem.
But asked at his pre-match press conference whether the England right back was fit and available, the boss said he would wait until training before knowing how Walker and the rest of the City squad were shaping up.
“Right now, I don't know. We have training in a few hours and we will know it. Right now, I don't know,” Guardiola revealed.
City will travel to Old Trafford lying in third place in the table with the latest Manchester derby once again set to attract huge attention.
However, the boss downplayed suggestions that it would represent the biggest game of the season.
He said his work at the CFA ensured he was solely focused on getting the best out of his squad and he was looking at the game and not the occasion.
Instead, he said the derby was more importantly an opportunity to try and gain another three important Premier League points.
“I don't think so (that it is the biggest game). Maybe, for some people,” Pep added.
“We try to make every game important. The derby is special for sentimental issues but at the end it is the same result.
“It is not a final, it is one more game.
“I wake up in the morning and come to the training centre and am here for 10-14 hours here and after I go home.
“I am not going to the pubs to drink a beer so I can’t imagine the atmosphere.
“It is normal, but I have to be cold in my mind, in my head to know what to do, to do our best.
“No more than that.”