Celtic are believed to again be showing considerable for Leicester City defender Matt Mills.
The 25-year old appeared to have turned down a move to the Scottish champions last week when he was set to join Bolton on loan with the option of a permanent deal.
But Record Sport suggests that proposed move has now stalled allowing the Hoops to re-join the race for the £3million-rated former Reading centre-back.
Celtic boss Neil Lennon is keen to bring in a quality central defender after losing Daniel Majstorovic and Glenn Loovens in the off-season and Mills has been identified as the man to lead the Parkhead back four.