Daniel Farke felt the red card for Emi Buendia in the 0-0 draw with Middlesbrough was harsh.
The Argentine was shown a second booking after he and George Saville went sliding in for a loose ball.
The referee initially gave Middlesbrough the advantage, indicating that he was not going to produce a booking for Buendia who had already been cautioned. However, after the ball went out of play, and following strong protests from the opposition bench and players, he dismissed the Norwich City midfielder.
“You are of course disappointed in such a moment,” said Farke. “It also feels a bit unfair if such a player, that often and receives many, many hits, is sent off in such a situation and not allowed to finish the game.
“I think the yellow-red card was harsh because it was a fight for the ball, both players went to tackle and he (Emi) came at it at one-point of a second too late and tries to pull his leg out of the situation and an experienced opponent makes a bit more out of it.
“On the other hand, you can also argue and say, if you are on a yellow card you have to be a bit more careful in these duels and that you don’t give the referee a decision to make.
“My feeling though in this moment is that it was harsh. There is no intention, no danger that he would injure the player and not a tactical foul.
"I think though that he (Emi Buendia) will have to learn and be a bit less naive, for his future, because it was quite costly for us today and it will cost him some game time.”
Speaking about the 0-0 draw, Farke added: “It is not what we wanted, if I am honest. We wanted to return back with three points into the dressing room. So for that the first emotion is one of disappointment but overall, sometimes you have to accept that it is a difficult day in the office, and this was one of those days. Middlesbrough were spot on and concentrated on their defending. I got the feeling in the first half that we were dominating this game, but our offensive players should have stayed a bit higher up the pitch to then have the energy where it really counts in the final third. We had good chances when I think about Mario’s (Vrancic) good situation out of 10 yards, but I got the feeling that we didn’t create enough.”