The Black Cats manager has warned his squad they have to be more professional on the pitch after seeing his struggling side receive a number of dismissals in recent matches
Lee Cattermole and Andrea Dossena were both sent off against Hull City in a game Sunderland lost 1-0, while Wes Brown was dismissed as Poyet's men suffered a 2-0 defeat to Stoke City last weekend.
Brown's red card has since been overturned by the Football Association's disciplinary panel, but Poyet is concerned his squad are setting a worrying trend.
| SUNDERLAND LATEST
|4/5||Sunderland are 4/5 with Coral to be relegated this season
"They know there is a limit, and they need to be careful. I hope it never happens again, but we'll see.
"We all make mistakes, and there is no explanation why you do it. It happens in a split second. But if you do it every week, you've got a problem."
The Sunderland boss had specific words of caution for Cattermole, whose red card against Hull was his sixth during his time at the Stadium of Light.
"When someone does something really, really stupid and it's repetitive, he doesn't have a chance with me," Poyet added.
"They need to be professional."