The 34-year-old has been searching for permanent pastures since leaving Premiership side Bolton Wanderers for the second time back in September.
Recently, Warhurst was at Carlisle United where he made one appearance before deciding not to remain at the club for family reasons.
During the summer, the former Blackburn Rovers, Manchester City and Crystal Palace man trained with Oldham Athletic and had talks over a possible move to Bristol City.
In October, he signed a month-long deal with Chesterfield before moving on for a short spell with Barnsley in December.
In early February, Warhurst trained with Queens Park Rangers before briefly joining The Cumbrians.
Meanwhile, the Meadow Lane club have opened contract talks with central defender Nick Fenton.
Mills hopes a deal can be reached to keep the highly-rated 24-year-old, with the Manchester City man's current contract set to expire in the summer.
"I have had talks with Nick about a new contract," Mills told the Nottingham Evening Post.
"He wants to stay here and would like a new deal and it is something we are discussing.
"Hopefully, something can be sorted out soon."
