Leinster hooker Sean Cronin says Northampton's Dylan Hartley's actions last week were rash but he remains a positive force for the Saints.
Hartley was sent off for hitting Sean O’Brien in the face last weekend and could face a long ban which could see him ruled out of some of the Six Nations.
"I always thought he was pretty calm and level-headed," Cronin told the Northampton Chronicle.
"When he came on that time we managed to get two scrum penalties and I don’t know whether that fired him up a small bit.
"It was obviously rash what he did, stupid, and he’ll have to deal with it this week, whatever happens.
"He’s a class player. You could see how well they had done over in Australia and in the autumn series so I’d say there’s no one kicking themselves more than he is this week.
"I presume he’s going to get a ban, but Mike Haywood’s a top-quality hooker and it could galvanise them as well."