Antonio Conte says Chelsea are contemplating an appeal against John Terry's dismissal in Sunday's 4-1 FA Cup third-round win over Peterborough.
A routine victory over League One opposition was complicated by Terry's sending off and Conte believes referee Kevin Friend made the incorrect decision.
Terry, making his first start since the EFL Cup exit at West Ham in October and first appearance since November, was adjudged to be last man when he fouled Lee Angol and was shown a straight red card by Friend. He faces a one-match ban.
"I think it wasn't right, this decision from the referee," Conte said.
"He didn't take the opponent and also the second reason was because behind John there was (Branislav) Ivanovic to cover John.
"You have to respect the referee's decision, but in this case maybe we will do an appeal for this situation.
"The situation is very clear and I think John didn't deserve this.
"It's a pity when this happens, because the red card is not good."
Terry's time at Stamford Bridge could be nearing an end. He was 36 last month and his contract expires in the summer.
In January 2016 Terry disclosed that he had not been offered a new deal and that he would be leaving that summer.
But he was later offered and then, after a period of deliberation, signed a 12-month extension last May, concluding an issue which had shrouded the second half of last season for the Blues.
Conte insisted the decision on the future of Terry, who made his first-team debut more than 18 years ago, will be made with the club and was adamant he was happy with the club captain.
"I'm pleased for John, because he's showing me great commitment when I ask him to play, when he doesn't play," Conte added.
"He's helping me a lot in the changing room. He's showing me to be a good player, but above all a good man."
Conte on Sunday recalled Nathan Ake from his loan spell at Bournemouth. The Dutchman provides additional competition for Terry as he can play in central defence, or potentially as a left wing-back.
"Ake gives me important options," Conte said.
Conte remained coy on transfers, with the winter window open, and declined to address speculation of a move for Swansea striker Fernando Llorente, with Michy Batshuayi reportedly going in the opposite direction temporarily.
Conte made nine changes to the team which began last Wednesday's loss at Tottenham, which saw the Blues' 13-game winning run in the league come to a halt.
Batshuayi started, scoring his first goal since August as Chelsea took a 3-0 lead prior to Terry's dismissal, netting between strikes from Pedro and Willian.
"Now it's important for him to continue in this way and to give me the opportunity to have another solution in our squad," Conte said.
League One Peterborough claimed a consolation when Tom Nichols pulled a goal back, but Pedro struck his second to complete victory.
Peterborough boss Grant McCann said: "We could've come here and defended deeper and tried to frustrate them.
"But I thought we may as well come here and give it a go. I don't think we came here and disgraced ourselves."