Butler has signed a one-year deal with neighbours Scunthorpe United after rejecting the offer on the table to continue his time at Rovers beyond four and a half years.
Boss Grant McCann revealed the 35-year-old had been offered a one-year playing contract with a two-year coaching deal to follow on – an arrangement with the flexibility to allow the centre half to continue playing beyond next summer had all parties been willing.
Butler says his wages would have been reduced, and with Scunthorpe offering more, he felt he had little choice but to move on.
“It’s happened really quick,” he said.
“I got offered a contract by Donny and they put forward what they thought was an acceptable offer but for myself I couldn’t accept it.
“Financial-wise, it wasn’t good for me.
“I appreciate the coaching role and it’s something that I'll look to do in the future, wherever that may be.
“I just wanted to play but with the offer being lower than before, it just wasn’t feasible.
“I’m not a money-grabber, but when you finish in the top six you don’t want a pay cut.
“You have to think about the financial side of things at any stage of your career.
“If there is an offer there that’s better than what you’ve been given then as much as you want to stay, you can’t.
“It's like a normal job – if someone gives you a demotion, you’re going to leave if you can get more money.”
Balby-born Butler – who made 222 appearances for Rovers – said it was difficult saying goodbye to a club he first joined in October 2014 on loan from Sheffield United, a deal which was made permanent the following January.
“There’s players, like James Coppinger especially, who have been there since I turned up and have been amazing for the club and the other players,” he said.
“We’ve roomed together a lot.
“It’s hard to say goodbye to players because you become friends. You spend every minute in each others’ pockets.
“It was difficult to say goodbye.
“But I think everyone knew what was what and you move on.
“I just have massive thanks for every single player I played with because they’ve made my job easy.
“I said that to them before I left. You made me look good because you can only be as good as the person next to you.
“I was disappointed to leave.
“I live five minutes from the training ground and I’ve spent five good years there.
“But I’m moving to a club where I started my career. Not many people can say they can go back to the club where they started towards the end of their career.”