Pierre-Emile Hojbjerg apologised to Southampton supporters following his red card in Sunday's 3-1 defeat to Manchester City.
Hojbjerg had earlier scored Southampton's equaliser after David Silva put City ahead in the Premier League fixture – the Denmark international beating Ederson with an emphatic drive.
But James Ward-Prowse's own goal and a Sergio Aguero header before the break ultimately gave Southampton too much to do.
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Hojbjerg was then shown a straight red five minutes from the end for a wild lunge on Fernandinho, meaning he will serve a third suspension this season.
In a statement released on Saints' Twitter account, the midfielder said: "I would like to apologise about my red card and letting my team-mates down.