Man City boss Guardiola admits Haaland a doubt for FA Cup semi-final
Guardiola subbed both Haaland and Kevin De Bruyne off ahead of extra time in a surprise move in City's penalty shootout loss to Real Madrid that extinguished their hopes of capturing the treble for a second successive season.
"Erling felt something, a muscular issue," Guardiola told reporters on Friday. "We will see.
"Kevin felt exhausted, so tired, after five months out injured (at the start of the season), so that's normal."
It is not surprising, Guardiola added, that his players are feeling the effects of a gruelling schedule, which is a byproduct of the team's success.
"It's normal, with the amount of games we've played this season and in the previous seasons," the Spaniard said. "There's not much time for recovery, we played extra time and the intensity we play. We are not machines, the fatigue is there."
City had appeared on pace to become the first team in history to win the treble - Champions League, FA Cup and Premier League - twice before Wednesday's defeat at the Etihad.
They are still on course for the double, having taken a two-point lead atop the league standings last weekend with six games remaining.
Asked how his team can move on from their Champions League heartbreak, Guardiola said: "We don't have an option, we can't feel sorry for ourselves.
"We don't have time to reflect, we'll do that in the summertime. You compete to win, but sometimes you lose games, and that's what happened."
Guardiola's men will face former City winger Cole Palmer on Saturday at Wembley, following the 21-year-old's four goals in Chelsea's 6-0 rout of Everton on Monday that drew him level with Haaland as the league's top goalscorer this season. Haaland and Palmer both have 20 goals.
The first question posed to Guardiola at Friday's press conference was about Palmer, who was sold to Chelsea last year.
"He's an exceptional player, we knew when he was here. I've said many times, I didn't give (him) the minutes that maybe he deserved and now he has at Chelsea. I understand completely," the manager said.
"He's a shy guy with a lot of potential. It is what it is. He's playing fantastically well. But he was asking for two seasons to leave. I said 'no, stay'. But he still said 'no, I want to leave'. What could we do?"
City have won the FA Cup six times. A victory would set up a final clash against either last season's runners-up Manchester United or Championship (second tier) side Coventry City.