City’s 2-0 victory over Fulham in the Carabao Cup was overshadowed by De Bruyne limping off with an apparent knee problem with five minutes remaining after falling awkwardly in a clash with Timothy Fosu-Mensah.
The Belgium international was making only his second start of the season following knee ligament damage.
And Guardiola hopes De Bruyne will not be sidelined for long heading into a crucial period of the season.
“He’s being checked with the doctors so I don’t know right now (how he is),” he said.
“I think today Kevin is back, the Kevin we know. He spent a lot of time injured but made a huge effort in Donetsk against Shakhtar and played a few minutes against Spurs in a difficult situation because of the pitch and the physicality.
“Today again he was involved with everything offensively and defensively, so hopefully what happened in the last minutes is not serious.”
Phil Foden and Brahim Diaz, who netted twice, both impressed as City eased into the quarter-finals, where they will face Leicester or Southampton.
Guardiola insists regularly leaving out the teenagers from his Premier League team is one of the hardest parts of his job.
“You cannot imagine,” he said.
“There are no words to explain how tough it is. They make my job so easy on one side because it is a joy to train them but at the same time it is so difficult because they don’t play.”
Fulham boss Slavisa Jokanovic made only three changes from the defeat to Bournemouth at the weekend as he bids to find some continuity.
“It’s not so strange in this country that teams play Saturday, Tuesday, Saturday,” he said.
“We have three games in nine days so in the end I try to respect the competition. We know we will play a second City team – if I can call it that when you have players like De Bruyne, Gabriel Jesus, Danilo…
“But we try to play our best football and be competitive and pass to the next round. We try to show our best face.
“We’ve seen some kind of improvement in this game for sure. In the end I am unhappy with the result but there are at least some positive signs that I want to look to.”
The Egypt international, who said as a 10-year-old boy playing PlayStation he would almost always pick the Reds as his team, formulated his strategy when he left his homeland to join Basel in Switzerland six years ago.
Liverpool tried to sign the 26-year-old, who became the quickest to 50 goals for the club after a double in his 65th match against Red Star Belgrade last week, in 2014 but were pipped by Chelsea.
However, he finally completed his move, from Roma, last summer and went on to score 44 goals in his debut season.
“It’s famous all over the world – and with a lot of supporters in the Middle East – so I think I first heard of Liverpool when I was 10 or 11,” he told liverpoolfc.com.
“The story of me playing as them on my PlayStation is true; sometimes it was as other teams, but most of the time I was Liverpool.
“Back then, I could never have imagined I’d be here one day, but it was always a dream of mine and you have to try and follow them.
“When I went to Basel from Egypt I had a plan in my mind that I would hopefully one day come to Liverpool.
“There was a chance before, but at the time it didn’t work for both sides.
“When there was interest again last year, I was very interested in coming to Liverpool straight away in my head, but you also have to see what the plan for you is and how you will fit into it.”
Raheem Sterling has verbally agreed a new five-year deal with Manchester City, according to reports.
The 23-year-old became British football’s most expensive player in 2015 when swapping Liverpool for the Etihad Stadium in a deal rising to £49million.
Sterling has come on leaps and bounds under the tutelage of manager Pep Guardiola, but recently talk has grown over the forward’s future, with his existing deal set to expire in 2020.
However, it is understood that a new and improved five-year contract has now been verbally agreed with the England international to keep him at the Etihad Stadium.
Sterling played a key role in City’s record-breaking title triumph last term and this season has netted four goals in eight Premier League appearances in all competitions.
The 23-year-old’s future at the club has been a hot topic since the start of the season.
Guardiola said ahead of August’s Community Shield encounter with Chelsea that there was “no doubt” City wanted him to stay, but left the situation in the hands of Sterling’s representative and City’s director of football Txiki Begiristain.
There has now been a breakthrough in terms for the former Liverpool flyer, who started his career in the youth set-up at QPR but left without making an appearance in 2010.
Sterling, who was raised near Wembley Stadium, remains close to his London roots and will reportedly be investing in an academy in the north of the capital.
‘Believe in a Dream’ is reportedly what it could be called, with the forward said to be waiting for potential premises to become available from Brent Council.