Butler has re-aggravated the back injury which kept him sidelined for part of the summer, Otago coach Mike Hesson said yesterday.
But Butler's bad luck is a slice of good fortune for Redmond, who is set to replace the hard-hitting pace bowler.
"I don't know that it has been confirmed by Gloucestershire but, having spoken to Aaron [yesterday], he has basically been signed up to play in the last eight rounds of the twenty/20 tournament, which is obviously pretty good," Hesson said.
Butler's injury was not has bad as initially reported but Hesson said the 28-year-old needed to come home and get the injury right so he could be available for the Blacks Caps tour of Sri Lanka in August-September.
"It is pretty similar to what he had earlier on in the year for us, and it is not something that is going to be fixed in a week or two. So he actually needs to come back and give it a decent rest.
"It is a little frustrating for him. But I've spoken to him a few times and he is pretty optimistic."
Redmond also had his injuries problems with a groin injury restricting his involvement for Otago.
He started his career as a leg-spinner who could bat but has transformed himself into a handy top-order player.
The right-hander is a technician but also likes to score freely.
In 29 twenty/20 games has scored 623 runs at an average of 27.08, including one century and four 50s.
His strike rate of 133.97 is more than useful and he has the ability to pace an innings beautifully.
"He has been over there doing well at club cricket but to get an opportunity to play county cricket is something he is pretty excited about."
Gloucestershire has lost five of its first seven games.
The McCullum brothers, Nathan and Brendon, are both making a mark on the tournament.
Nathan took three wickets on debut for Lancashire last week and Brendon top-scored with 34 to help Sussex defeat Surrey by 39 runs earlier this week and consolidate its spot at the top of the competition table.
