Neal Ardley is waiting on video evidence before slamming Dannie Bulman for costing AFC Wimbledon three points at Exeter City.
The midfielder was shown a straight red card in the first half for an apparent two-footed challenge on Exeter's Connor Riley-Lowe.
Adebayo Akinfenwa had given Dons the lead with a worldy strike, but the hosts fought back in the second half with three goals, before a late own goal gave Dons ultimately doomed hope.
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Ardley said: "We didn't defend well enough at times, one-to-one defending wasn't good enough.
"When we did get into the dangerous areas, they moved it well and they caused us problems.
"After a really good start, it all went wrong and 23 minutes in they tell me Bully went in two-footed, if he did then he's cost the team a long trip and an away performance really.
"To concede a really soft, soft penalty is really hard to take."
Action from Exeter City v AFC Wimbledon
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