The Bayern Munich boss does not want his star man to rush back from injury after making his comeback in midweek in the 5-0 win over Hamburg.
The Germany international made his comeback on Wednesday after recovering from ankle surgery, and completed 25 minutes as the Bavarians beat Hamburg 5-0 in the quarterfinal of the DFB Pokal.
However, the Spaniard does not feel that his star midfielder is yet able to feature from the start.
"It's still a bit too early," he said at a press conference on Friday. "He's an outstanding player. I hope that he can improve every day and every game so he gets his fitness."
Bayern faces a Champions League trip to Arsenal on Wednesday but Guardiola was keen to deflect attention away from their European fixture.
"I don't know where that'll be in our heads," he said. "The next game is always the most important."
Guardiola also pointed out the threat posed by Christian Streich's side which recently claimed the surprise scalp of Bayer Leverkusen.
"They're very aggressive," he said. "This isn't fun, but work. We have to run, run and run."