Jim Mallinder has confirmed Dylan Hartley will be pleading guilty at his citing hearing in Dublin on Thursday.
The Saints skipper will be in the dock in Dublin after being pinned for an incident involving Ireland hooker Rory Best during Northampton’s defeat to Ulster last Friday night.
Hartley has been accused of foul play after appearing to use an arm on Best, with Mallinder admitting his player’s actions were wrong.
And the director of rugby now expects to lose his captain to suspension for this weekend’s return clash with Ulster at Ravenhill.
“He’s done something he shouldn’t have done,” said Mallinder. “It’s not the biggest incident in the world, but we’ll hold our hands up and Dylan will be saying sorry.
“I do expect him to miss this weekend’s game but we hope to get him back as soon as we possibly can.”
Mallinder says Saints continually educate their players, first-team to academy, about their on-pitch conduct.
But he admits there’s a fine line between controlled aggression and overstepping the mark, as Hartley did on Friday.
“Discipline wise it’s very, very tough in terms of players playing on the edge,” said Mallinder. “You don’t want them to be soft, you don’t want them to take backwards steps but they’ve got to play within the laws and it’s a question of educating them and making sure they’re aware of the responsibilities to the team, the club and the fans.
“It’s ongoing with everyone. It’s not just Dylan Hartley, it’s everyone in the squad. It starts when they arrive here and it goes until the day they leave.
“It’s not easy, but it’s not like it was 5, 10 years ago, it has changed. There are cameras everywhere and you can’t do anything.”