Southampton manager Ronald Koeman did not punish Victor Wanyama despite picking up a third red card of the season last weekend.
The 24-year-old will miss Saturday's trip to Swansea after being shown a straight red card for a challenge on West Ham's Dimitri Payet.
Wanyama will miss a further four matches as it was his third sending off this season -- all of which have come since November -- but Koeman believes the midfielder was unlucky to be dismissed this time.
"We did [discipline him] after the second yellow card [in the 1-0 defeat to Norwich in January] but we did not this time," he said. "I think Victor was a little bit unlucky.
"In my opinion, that red card was totally different to the second yellow, for example, against Norwich. In my opinion, that was more of a stupid foul.
"Now he was unlucky because his intention really was to play the ball. He missed the ball and the referee took a hard decision.
"One day later I saw a tackle from [Mathieu] Flamini against Bournemouth and it was yellow. Maybe that tackle was more red than the tackle of Wanyama."
Wanyama was understandably disappointed and frustrated with a red card that Koeman believes the midfielder needs to learn from.
"He was angry, he was disappointed because he knew about the five-match suspension," he said
"He was really showing to be disappointed and he said to me that he was unlucky because his intention was to play the ball.
"I have sympathy for honest players and Victor is one of them.
"His intention is to play the ball but it was his third one and he has to learn. If you don't learn from this, then you never learn and he has to learn that sometimes you cannot take that risk.
"We always tell defenders 'stay on your feet, do not make that tackle' and he is strong enough to use his body to win the battle."
Saints welcome Matt Targett and Steven Davis back from injury for their game with Swansea, but Koeman is frustrated that Wanyama will not be part of the side.
"[I am] very disappointed," he said.
"First of all, for the player by himself and also for the team because he is an important, key player for the team, who is normally always in the line-up.
"He is suspended for five games and it is a long time but we have to accept and, like in other positions in the team, we have enough competition to replace Victor."