Forwards coach Dorian West has warned Saints that success will elude them if they fail to improve their disciplinary record.
Jim Mallinder’s men have been hit by eight yellow cards in their past 13 matches, while Dylan Hartley has been dismissed during that time.
That is in contrast to the first 11 games of this campaign, when the Aviva Premiership champions only suffered one sin-binning, with Alex Corbisiero yellow carded at Wasps in September.
Australian prop Salesi Ma’afu will now serve a two-week ban for striking London Irish rival Tom Court in last Friday’s game at Franklin’s Gardens.
And when asked whether Ma’afu, who was also banned for a week last month, had been spoken to about his discipline, West said: “We talk to everybody about it. It was part of our meeting the other day, we talked about the penalties we gave away.
“You get a report from an independent referee and there’s a few things highlighted on there that could have gone against us and things we need to keep working on.”
Saints will need to be squeaky clean to get a result in the huge top-of-the-table battle at Bath on Saturday.
And West added: “We don’t want to give penalties away, we don’t want to lose people to the sin bin, we don’t want people to be banned.
“If you want to be successful you need to have your players on the field for the entire game so it’s something we’re working on, something we’ve talked about.”