BBC Scotland said the new line-up for Afternoons, in place from 1 June, would “bring audiences a lively mix of music, chat and big interviews, with a focus on the vibrant arts, culture and entertainment scene in Scotland and beyond”.
The current afternoon presenters, McManus, Len Pennie and Nicola Meighan, will step down.
McManus began presenting Afternoons in 2023, and also presents the Entertainment Mix.
She has appeared in a number of BBC Scotland documentaries, most recently one about her journey to sing for the Pope.
Victoria Easton Riley, head of audio and events at BBC Scotland, said: “Grant is already a firm favourite with Radio Scotland audiences through The Vinyl Collective, and Arlene is an experienced radio and television broadcaster who we know brings a real warmth and connection to listeners.
“We’re enormously grateful to Michelle, Len and Nicola for the energy, creativity and passion they’ve brought to the programme.”
Grant Stott said: “I’m absolutely delighted to be returning to Afternoons. The Radio Scotland audience is a warm, curious and engaging bunch and I can’t wait to dive back in.
“We’ll be bringing listeners everything they need to stay plugged into Scotland’s buzzing arts and culture scene, all with the perfect soundtrack.”
Arlene Stuart said she was excited to be hosting the show on Friday afternoons.
“I love radio and the connection it brings with listeners, I can’t wait to get behind the mic and get the conversations started,” she said.
Mornings, presented by Connie McLaughlin Monday-Wednesday and Stephen Jardine Thursday-Friday will continue to be broadcast between 09:00-12:00.
The changes come six months after a new-look radio breakfast programme aired on BBC Radio Scotland, front by Laura MacIver and Martin Geisler.