The 30-year-old, who was signed as the Millers' marquee arrival in the summer by Steve Evans, has endured a nightmare few months at the club, which saw him leave for Birmingham on loan in November.
However, Blues did not want to extend the deal and Redfearn has also shut the door on any hopes he may have had of turning things around in South Yorkshire.
One-time record signing Jordan Bowery, who cost £250,000, has also been told he has no future at the club after he returned from an unsuccessful loan spell at Bradford.
The grim futuret of their Millers careers was highlighted by the fact that Redfearn chose not to use them in Saturday's FA Cup loss at Leeds, despite having a depleted squad.
The Millers boss said: "Greg is not in our plans. He needs to go and look somewhere else if he is to prolong his career.
"He needs to go and find another club and the same with Jordan Bowery.
"That’s football. Players
come in, players go out and these two players need to go and find new clubs.
Hopefully somebody comes in for them.
"I’m not knocking them as
lads, they’re good lads, but they just need to move on. We need to get better
in.”
Halford, who is thought to be the club's top earner, has had a desperate stay in South Yorkshire after error-laden performances at centre-half saw him stripped of the captaincy after just eight games.
He played just one more time for the Millers and has not featured at all under Redfearn following a reported fall-out with assistant Eric Black that led to a series of tweets.
Bowery's time has been less dramatic, but he has failed to deliver on the then-club-record investment that brought him to the club from Aston Villa.
He scored six goals in 44 appearances.
