Lawes has been nursing shoulder injuries and was withdrawn at half-time in the 37-5 Champions Cup quarter-final defeat at Clermont Auvergne earlier this month.
He missed the Aviva Premiership loss at Exeter last Sunday, with Saints keen to give their lofty lock time to recover.
But Mallinder insists Lawes will be available for the crucial league battle with Saracens, who are now just six points behind Saints in the standings.
“Courtney will be fine,” said the director of rugby.
“He’s got a couple of bad shoulders - one of which is sore, so we just thought he needed to have last weekend off.
“It means he gets another week off this week and then he’ll be coming back fighting full on ready for the Saracens game.”