Midfielder Miguel Pallardo has signed a new one-year deal with newly-promoted Hearts while Danny Wilson leaves.
Liam Rosenior has thanked the fans of Hull City for "five wonderful years".
The ex-Spain international made 194 appearances for Wanderers between 2002 and 2008 but has no formal coaching experience since retiring from playing two years later.
Bolton sacked boss Owen Coyle on Tuesday following a lacklustre start to their bid for an instant return to the Barclays Premier League that leaves them languishing in 18th position.
In a stream of posts on his Twitter page evoking former boss Sam Allardyce and his one-time team-mates Kevin Nolan, Kevin Davies, Jay-Jay Okocha, Jussi Jaaskelainen, Youri Djorkaeff and Fernando Hierro, Campo urged Reebok Stadium chairman Phil Gartside to contact him in the wake of Coyle's departure.
In the course of four entries, he tweeted: "After to know what its happening in the BOLTON FAMILY I want to say that of corse (sic) I would like to help the club. I love very special moment in my life. Big SAM. Nolan. Davo. JJ Okocha. Jussy, Djorksef (sic), Hierro And all FANS OF BWCG (sic). My Family.
"Only I need to receive a call OF PHIL GARTSIDE and I will GO to BOLTON IMMEDITALY (sic) TO HELP TO THE CLUB WITH MY EXPERIENCE. Ok. I would try to speak WITH PHIL GARTSIDE And after meeting the fans will know of I will GO again to Bolton or NOT."