Cowan will ride the pine at Carisbrook and Toby Morland will earn just the second start of his Super 14 career.
While the word "dropped'' has been phased out in the professional era and replaced by terms like rotation, the decision to demote their most experienced back for a home game against an unbeaten team is the closest thing the Highlanders have to a bombshell.
"Jimmy's had a massive workload through this campaign. He played all the pre-season games and has started every game in the competition,'' Moore told the Otago Daily Times yesterday.
"We said from the outset we needed to manage workloads and we were going to have to make some hard calls.
"Jimmy understands the situation. He sees it from the holistic team point of view.''
Morland's has been an interesting career. He made one appearance for the Highlanders each year from 2004-06, always as a mid-season replacement, and has had to be content with snatches of game time as a contracted player during the past two years.
He does not have Cowan's physical strength or defensive ability but Moore has faith he will do the job against a talented Sharks backline.
"Toby is a very good supporting halfback. He knows how to run through the gainline and get himself into good positions.
"The other big thing is his ability to get the ball away at pace.''
Moore has made four other changes to the side that broke a six-game losing streak with a 29-20 win against the Lions.
Niva Ta'auso replaces Brett Mather at centre, Adam Thomson gets a rare start at blindside flanker, Hoani Macdonald moves from the flank to lock, and Chris King replaces Jamie Mackintosh at loosehead prop.
Moore has shuffled his front row a little and said it was simply time for Mackintosh, who has started every game this season, to take a break.
"We're really happy with where Jamie is at. I think he's had a tremendous campaign in his first full season.
"He's been playing international props week in and week out, and that takes it out of you. And we've got some big packs that we're meeting over the next few weeks.''
Thomson's efforts off the bench have finally been rewarded with a start. Moore feels his style of play will be well suited to the Sharks.
The only danger the Highlanders have is being caught short in the loose. With Steven Setephano and Alando Soakai still out injured, there are no specialist reserves, and Moore is resisting the temptation to put temporary replacement George Naoupu on the bench.
James Wilson gets a second straight start at first five-eighth after performing well against the Lions.
"I think James showed us enough to say he deserves another crack at what is his favoured position,'' Moore said.
''He took the ball to the line well and ran the whole ship. And it was particularly pleasing that his goal-kicking was good.''
Moore has still not settled on which 26 players he will take to South Africa. The team flies out on Saturday.
