Bailey, who turned 34 earlier this month, played for Leigh Centurions last season following an acrimonious exit from Toronto Wolfpack.
But he has now joined their Championship rivals as he looks to secure a contract for 2019.
Bailey won six Grand Finals with Leeds where he was a long-term team-mate of Delaney, the Australian second-row who has moved from Headingley to Post Office Road ahead of next term.
Featherstone have also recently taken another ex-Rhino on trial - Jordan Tansey.
“I loved playing with Brett,” said Leeds-born Bailey.
“It’s been four years since we played together, but he’s one of my closest friends.
“Jordan Tansey, I came through the academy at Leeds with him, so It would be special to spend my career at Featherstone with two good friends.”
With more than 300 senior appearances, Bailey will clearly bring plenty of experience to Featherstone - looking for a new coach following Jon Duffy’s exit to Leigh - along with Delaney.
“We’re good talkers on the field and lead the way,” he said.
“We’re good leaders; I’ll add experience in the pack guiding young fellas in the wrestle and their skills and just a lot of talk.
“As long as we’re a close knit group we’ll do well this year.”
Bailey, who has also had spells at Hull KR, Castleford Tiger, Warrington and Workington Town since leaving Leeds at the end of 2014, added: “I just want to win the supporters over really, like I do at most clubs.
“Everyone’s got a persona of me, but I just want to win the Featherstone fans over and have a great year.”