Jack Ross will reflect on Max Power's red card before deciding whether to appeal to the FA.
The midfielder was shown a straight red in Sunderland's 1-1 draw with Oxford United in the 19th minute for a foul on Marcus Browne.
It left the Black Cats a man down for more than 70 minutes of the League One clash and Ross admitted at first he thought it was a red but on second viewing he believes referee Mark Heywood got it wrong.
The Sunderland fans were not happy with Heywood's performance and chanted 'You're not fit to referee' at the official throughout.
Power is facing a three-game ban for the red card, and the suspension would start for the visit of Fleetwood next Saturday, Checkatrade Trophy games don't count.
"At the time I thought it may have been a red on my first viewing," admitted the Sunderland boss.
"I had the benefit of watching it again, having watched it again I don't think it is [a red].
"Max does go at first to be really cynical but then Max pulls his leg back, I think it is still a caution but not a red card.
"I think he gives the referee a decision in that sense. I don't agree with it, but he gave him a decision."
The Sunderland boss was angry that the visitors were not also down to ten men, Shandon Baptiste only shown a yellow for a foul on skipper George Honeyman.
Ross added: "I think there should have been another red in the first half [foul on Honeyman].
"There were decisions that didn't go our way and we lost a wee bit of discipline, frustration got the better of us and that is natural.
"That was something that was stressed at half time, we had to keep control of that.
"I don't want that to distract from the opening period, we weren't good enough in the opening period.
"The reaction after was good."
When asked whether Sunderland will appeal, Ross said: "I will think long and hard about it.
"I think the arguments why they make decisions are always weighed in the officials favour.
"Second half there was a blindingly obvious yellow card and we don't get it.
"The explanation was because our player wasn't going anywhere. I will reflect on it, it is easy to dive in and say yes we will appeal it, I will reflect and make a decision."
Oxford United boss Karl Robinson didn't think Power should have seen red but did think Chris Maguire should have been given his marching orders.
The Sunderland forward was booked and then warned several times before being subbed at the break, Charlie Wyke coming on and scoring the equaliser.
Robinson said: "I love Max, he is a great kid and I have known him a long time.
"I don't think it was a red. I thought Oviedo should have gone, he volleyed my player.
"Baptiste should have been sent off for a second booking but so should Maguire.
"He got booked and then made four consecutive fouls. Their manager knows that, that's why he made the sub.
"The least sending off happened today, in my view. I feel sorry for Max but you won't get that overturned - not with our FA, they are not very good at it.
"It is a waste of time and money. There is no common sense within the disciplinary panel."