The Owls midfielder, making his first start of the season, went off early after a rash challenge on Sone Aluko. The two players had battled for the ball and upon losing the tussle, Matias flew in late from behind and referee Graham Scott brought out the red card.
Matias would have been unlikely to have been in the picture for a place in the side for the play-offs but will now miss the games anyway through suspension.
Carvalhal didn't necessarily disagree with the decision, but felt that other similar tackles had gone unpunished.
"I saw a lot of situations like that where the player has not taken a red card," he said. "I respect the decision of the referee but I saw often this kind of situations, especially in the midfield and the referee has given a yellow card. I respect the decision but I saw similar situations with a yellow card...a lot."
Owls full-back Liam Palmer, another one of ten changes made by Carvalhal for the match with the Huddersfield game very much on the coach's mind, admitted that Wednesday were given an uphill task following Matias' dismissal.
He said: "I didn't see it clearly myself as I was running back but I asked Marco and he said it wasn't two-footed, it wasn't malicious, so a bit harsh from our point of view and it was a totally different game after that.
"It spoiled it as a contest, in that heat as well and they keep the ball very well. To have that advantage, it took it away from us really."