Sunderland boss Martin O'Neill has ordered captain Lee Cattermole to clean up his act.
The 24-year-old was dismissed for the fifth time in his Black Cats career for an ugly lunge at MK Dons defender Adam Chicksen during Tuesday night's 2-0 Capital One Cup third-round victory, and will now have to sit out the next three Barclays Premier League games, including the derby clash with arch-rivals Newcastle.
O'Neill, who has joked publicly about his skipper's disciplinary record in the past while taking the matter more seriously behind the scenes, is rapidly running out of patience with a man whose robust approach is earning him an unenviable reputation.
The Northern Irishman remains a fan of the positive aspects of Cattermole's game, but admits his on-pitch excesses are becoming an increasing problem.
Asked if he has considered the captaincy issue amid a debate among fans, O'Neill said: "I have had a wee bit more time to reflect on it, and certainly Lee has as well - he's got most of a month.
"He is obviously very, very sorry, but 'sorry' doesn't help us now, not only over that particular game itself, which we could have lost, but the games coming up now.
"We will see, but again, there are many qualities to him for one so young as a captain of the team. But you just can't be stepping over the mark like that."
Cattermole broke into the Middlesbrough first team as a tough-tackling 17-year-old, and his battling qualities have served his home-town club, Wigan and Sunderland well over the years.
But his charge-sheet is long and not very pretty - he has been dismissed a total of seven times and cautioned on 64 occasions - and O'Neill admits he must learn to strike a balance between controlled aggression and potentially endangering fellow professionals.
The manager said: "He does so many good things for us, both as a player and as a captain as well.
"But you can't be that rash. You can occasionally, but you have got to learn, and more so than ever before now.
"You can't be lunging in at players, your foot off the ground, now. You can hurt an opponent, that's obviously the problem and that's why referees are, in the main, cracking down on it.
"I always think you can learn if you really want to. I have always felt Lee, even though we have had a joke in here about it before, I have always felt that he is capable of doing that, capable of learning.
"He's an intelligent lad and I just think he has to think a little bit more about it.
"If you overrun the ball, sorry, you will just have to let it go. Let it go and don't be lunging in to try to win it and the possibility of being sent off the pitch."
O'Neill stopped short of claiming that referees are targeting his captain, but admitted his reputation does him few favours with officials.
He said: "What I do think is that his reputation definitely precedes him, and from that viewpoint, the referees are much less lenient with him.
"If you look at [Chelsea defender] David Luiz's challenge, for instance, against Stoke City - there's no doubt that if that had been Lee's challenge, he would have been sent off the pitch.
"He gives us a drive and determination and I look to him for that, that helps immensely.
"He can close players down as effectively as anybody I have known, but he just has to curb this lunging at players.
"I'm not even sure you would have got away with that there 15, 20 years ago. I doesn't really matter, there's a possibility of doing some irreparable damage to other players and you have got to cut that out."