Saints beat Saracens three times last season on the way to their first title in a decade, including a dramatic 22-20 win in the play-offs, with Sleightholme scoring a try in two of those games.
And he already has four in eight appearances this term – plus two against Australia and one each against South Africa and Japan during the autumn internationals.
Sleightholme played for England alongside clubmates Tommy Freeman and George Furbank – though the latter is doubtful for the Six Nations after fracturing his arm against Bulls.
“Playing international rugby is one thing, playing with some of your best mates is another – it was a huge thing for me,” he added.
“I made my debut in the summer in New Zealand and couldn’t really have anybody there – no-one could get over – but having my family at the autumn games was really cool.
“That’s the level I want to be performing at and I’ll just keep trying to get better every week and keep pushing for that.”
Scrum-half Alex Mitchell will play his 100th game for Northampton against Saracens, with Alex Coles leading the team in Furbank’s absence.
George Hendy will start the game at full-back after scoring one of their tries in the win over Bulls.
