Lewis Dunk was unaware he had already been booked when he was sent off for a second yellow card in Brighton's defeat at Bournemouth, according to team-mate Mat Ryan.
Albion captain Dunk was dismissed in the 73rd minute at the Vitality Stadium following a challenge on fellow England international Callum Wilson.
Referee Mike Dean had given Dunk an initial caution 11 minutes earlier, although television replays suggested Seagulls midfielder Yves Bissouma committed the foul on David Brooks.
Seagulls boss Chris Hughton said after the 2-0 loss that his team felt aggrieved, with goalkeeper Ryan revealing there was some confusion on the field.
"Lewis didn't know that he was already on a yellow card," Ryan told Albion's website.
"He's told us he wasn't aware, so it wasn't made clear to him – from memory both him and Bissouma were close to the incident.
"Perhaps if he was aware then he wouldn't be making a challenge like that because it's the type which is uncharacteristic of him and it's one that you make for the team as a sacrifice to break up play.
"If he'd known he wouldn't have made it."
Dunk's red card was sandwiched between goals in either half from impressive Bournemouth midfielder Brooks.
Brighton have now suffered three successive top-flight defeats.
That run has coincided with a three-match suspension for defender Shane Duffy, with regular centre-back partner Dunk now set to sit out the Boxing Day clash with Arsenal.
Australia international Ryan feels the Seagulls need to tighten up defensively to end their poor form.
"We have to work hard to get out of this run – if we keep clean sheets you can't lose a match and we need to get back to that," he said.
"We've been scoring a lot more goals this season, and so I'm confident that if we can start tightening up defensively the form will turn around.
"We want to get back to being hard to break down, but if you make little errors in this league you do get punished and it makes it even more difficult to come back when you're behind."
Bournemouth's victory was only their second in eight top-flight games and came after goalkeeper Asmir Begovic made a string of fine first-half saves.
Match-winner Brooks, who fired home from the edge of the box in the 21st minute before scoring a looping header 13 minutes from time, felt it was timely success.
"It's always important to get points on the board and try and climb the table at this stage of the season," he told afcb.co.uk.
"I think the results haven't been there but – apart from Liverpool (a 4-0 defeat) – the team's played well.
"We haven't just really got the bounce of the ball."
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