Defender George Baldock said his move to Championship club Sheffield United was too good an opportunity to pass up.
The 24-year-old signed a three-year deal with the League 1 winners on Tuesday after eight years at Stadium MK.
Baldock, like brother Sam back in 2011, leaves as a firm fan's favourite, and paid tribute to the club which gave him a shot back in 2009.
He told MKDons.com: “I’ve really enjoyed my time here and I’ll look back on my time with real fondness but this is an opportunity I felt I couldn’t turn down at this stage of my career.
“This is a great club and it’s the one that gave me my chance in the game. I’ll be forever grateful to the Chairman, the two managers I have worked under, the staff and the players that I’ve played with, as well as, of course, the supporters who have always been terrific with me.”
He added to SUFC.co.uk: "I'm absolutely delighted to have signed and committed my future to this impressive club."