Joey O'Brien has left Shamrock Rovers to become a part of Damien Duff's back-room team at Shelbourne, while the Reds also confirmed the departure of Ryan Brennan.
The Hoops confirmed on Monday that the 35-year-old defender will not be re-signing for the 2022 campaign as he instead links up with new boss Duff at Tolka Park.
"As a self-professed Rovers fan, we understand that this was not an easy decision for Joey to make and we wish him well," a Shamrock Rovers statement read.
O'Brien signed in 2018, making 85 appearances. He won two league titles and an FAI Cup under Stephen Bradley.
Duff laid out his vision for Shels at his unveiling two weeks ago.
"My ambitions are sky high but if I'm realistic, where Shels are at, they've been yo-yoing for a couple of years," he said.
"They're a sleeping giant but they have to stay in the league.
"Is it going to be easy? No. Is it going to be comfortable? No. But it is going to give me 24/7 focus, which is what I need.
"I know it's a difficult gig, I know it's a team coming up with not one of the biggest budgets. I don't like losing games and don't want to fail, I know a lot of the managers when they do fail in their first gig, they never get another manager's role again but that's stuff I am fine with."
Brennan confirmed that he won't be around for 2022 after writing on Twitter that the club had decided against renewing his contract.
A statement from the club read: "Shelbourne FC can confirm that Ryan Brennan has left the Club after three brilliant years with the Reds.
"With two of those years as Player of the Year, Ryan leaves Shelbourne as a Reds legend. He was instrumental in our promotion this year as we returned to the top flight.
"This season alone, Ryan scored 15 times with some of those crucial in our league winning season.
"The Club would like to thank Ryan for his brilliant service to the Club. Ryan was and will remain a real fan favourite. He will be remembered as a legend amongst the Shels fanbase and staff.
Speaking on his departure, Ryan said: "I would like to thank the Club, staff, fans and of course my teammates in the three year period I was there. They were some of my most memorable as a player to date.
"I will miss it as I felt a huge part of me had become a Red. Thank you for everything."