Northampton are currently in possession of the final play-off berth and know a win against the Warriors will see them into the semi-finals, regardless of what Exeter achieve against Saracens.
Mallinder has opted to keep faith with the side that overcame Exeter last time out with winger Chris Ashton set to play his final game at Franklin's Gardens.
"The job is only half-done," Malinder told the club's official website. "We put in a good performance against Exeter and the win put us back into fourth spot ahead of the last round of the regular season.
"However, we can still be caught and we do not want our place in the play-offs to be in other teams' hands. Only a win over Worcester will guarantee our place in the knockout stages and we have been fully focused on achieving that in training this week."
In their first season back in the Premiership, Worcester have achieved their primary objective of avoiding the drop and boss Richard Hill has made a number of changes as he looks towards next season.
In the back division, wing Josh Drauniniu, centre Ravai Fatiaki, fly-half Danny Gray and full-back Tom Arscott are all named in the starting line-up.
There are a further four changes up front with hooker Chris Fortey, prop Bruce Douglas and back rowers Neil Best and Matt Kvesic all featuring.
"There are no trophies on it for us, but it is a big end of the season for Northampton and is not going to be an easy place to go to," Hill said of the clash.
"However, we can relax and pick a very attacking team and people who have perhaps not had the opportunities in the first team. They are fresh and desperately want to produce. If we can get into the right areas then we can be dangerous."
Northampton: 15 Ben Foden, 14 Chris Ashton, 13 George Pisi, 12 James Downey, 11 Paul Diggin, 10 Stephen Myler, 9 Lee Dickson (capt), 8 Roger Wilson, 7 Phil Dowson, 6 James Craig, 5 Christian Day, 4 Mark Sorenson, 3 Brian Mujati, 2 Andy Long, 1 Soane Tonga'Uiha.
Replacements: 16 Ross McMillan, 17 Alex Waller, 18 Paul Doran Jones, 19 Ben Nutley, 20 Teimana Harrison, 21 Martin Roberts, 22 Ryan Lamb, 23 Tom May.
Worcester: 15 Tom Arscott, 14 Miles Benjamin, 13 Alex Grove, 12 Ravai Fatiaki, 11 Josh Drauniniu, 10 Danny Gray, 9 Shaun Perry (c), 8 Kai Horstmann, 7 Matt Kvesic, 6 Neil Best, 5 Craig Gillies, 4 James Percival, 3 Bruce Douglas, 2 Chris Fortey, 1 George Porter.
Replacements: 16 Ed Shervington, 17 Ryan Furniss, 18 Ceri Jones, 19 Ben Gulliver, 20 Sam Betty, 21 Jonny Arr, 22 Joe Carlisle, 23 Charlie Hayter.
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