The Sharks secured Premiership survival last weekend, meaning the pressure is now off for the final two games of the season.
In contrast, Northampton know there is still work to do as they bid to maintain their advantage over fifth-placed Gloucester in the race for a play-off place.
But Mallinder admits it will be no easy task this weekend, as Sale’s unpredictability means they will be a hard side to get the better of.
“It’s hard to say (how they will approach it),” said Mallinder.
“Sometimes as a team when the pressure’s off you can really come and play, but I don’t think that’s been stopping the way they’ve played during the past few weeks.
“They’ve been scoring tries for fun, they’ve been playing really well - down at London Irish, at home to Gloucester - really chucking the ball around and so they’re going to be dangerous.
“I can’t see them going away from that open style of play at the weekend because it’s going to be a nice day, the pitch is firm, so we’ve got to be on our very, very best.”
Should Gloucester fail to register a point against Saracens today, Saints will be sure of a top-four spot.
But if the Cherry and Whites prevail, Mallinder’s men will need a positive result against Sale, and the director of rugby is desperate for Saints to control their own destiny.
“We’ve got that opportunity (of winning a trophy) and that’s what you work hard for all season,” he said.
“We’ve gone 20 games at the moment, we know our destiny in our own hands and if we can get a win this weekend we’ve got a very good chance of a semi-final.”