Having left the Clarets at the end of the 2013/14 season, he signed for Barnsley but things didn't work out at Oakwell and they parted company over seven months ago by mutual consent.
Nothing was heard of him after that, but he returned to Ireland and has impressed Drogheda boss Johnny McDonnell having trained with the club.
He's still some weeks away from full fitness, but McDonnell said: "Keith is a fantastic signing. I've been tracking him for a while as he took the best part of a year out of the game to get married.
"I spoke to him a couple of weeks ago and he said he wasn't going back to England so I invited him to train with us. He was brilliant to deal with in terms of our finances and we are delighted to have him on board. His quality has stood out already in training."
Treacy joined the Clarets from Preston in August 2011 but, often due to personal reasons, was never able to establish himself as a first team regular. He made 66 league appearances during his three years at Burnley with just 29 of them starts, and scored five times, the last of which was our equaliser in the draw at Bournemouth in February 2014.
His last game for Burnley was as a substitute in the last home game of the promotion season, coming on for Danny Ings in the 1-0 win against Ipswich.
Now, aged 26, the Dubliner will be hoping to resurrect his career back home in Ireland.