Guardiola hopeful injured De Bruyne will be back soon for Man City
The 33-year-old suffered a suspected groin problem in the 0-0 draw with Inter Milan in the Champions League on Wednesday.
City next host Championship side Watford in the League Cup third round on Tuesday and travel to Newcastle United in the Premier League at the weekend.
"I don't think it will be long," Guardiola said of De Bruyne's expected return after City's 2-2 draw with Arsenal.
"I cannot say how long for, I don't know for Newcastle but it won't be long. (He has) discomfort in his legs."
De Bruyne was out for four months with a hamstring injury last season but made a memorable comeback at St James' Park with a goal in a 3-2 win over Newcastle in January.
City top the standings with 13 points after five games.