Crouch was shown two yellow cards in the opening stages of the Champions League quarter-final, first-leg tie as he brought down Sergio Ramos and Marcelo with late challenges.
While Tottenham had already gone 1-0 down to a header from Emmanuel Adebayor, the loss of Crouch left them toothless in attack and Harry Redknapp's side went on to suffer a potentially fatal 4-0 loss in Madrid.
Redknapp described the red card as "disappointing", but Carvalho has said that Crouch could have been treated with more leniency.
"I don't know if Peter Crouch should have been sent off," Carvalho said. "The first one was a yellow card. The second one? I don't know. Maybe the second one was unlucky for him and unfair for his team-mates."
Tottenham defender Michael Dawson also revealed that Crouch apologised for his dismissal. He said: "He (Crouch) was gutted. He apologised to the lads but we went out there to give our all and it didn't go to plan.
"I didn't see the bookings so I don't know if they were harsh. To have it happen so early on when you are playing a team like Real Madrid was disappointing."
Former Arsenal striker Adebayor netted twice at the Bernabeu, with Angel Di Maria claiming a stunning third and Cristiano Ronaldo finishing off the scoring when taking advantage of some suspect goalkeeping from Heurelho Gomes.
Ronaldo felt the red card was not decisive in determining the final result, but urged his team-mates to shun complacency ahead of the second leg at White Hart Lane.
"I'm very satisfied because the team put in a good performance. Recording a 4-0 win in the quarter-finals of the Champions League is a great result," Ronaldo told TVE.
"We shouldn't get carried away though. It's important to stay focused and to continue working very hard to hold on to our advantage. Anything can happen in football. We put in a good performance, regardless of the red card for Tottenham. We were always on top. We struggled a bit before the break, but improved in the second half."