Winger Pilkington has played just four times for Cardiff this season, and could find himself even further out of the picture after the Bluebirds' capture of Yanic Wildschut from Norwich City.
HITC Sport understands Pilkington is interesting Ipswich Town, Barnsley and Bolton, and the latter club, along with QPR, appear to have seized the initiative.
The Sun reports (page 6 of Friday's Goals pullout) that Cardiff are willing to pay £2 million for Bolton striker Gary Madine, and Pilkington's future could be inter-linked with that of the 27-year-old.
Given the choice of whether to join Bolton or QPR, Pilkington may favour the former having grown up in nearby Blackburn.
The Republic of Ireland international played for Stockport County, Huddersfield Town and Norwich before joining Cardiff thee-and-a-half-years ago.
Would Pilkington be a good signing for Bolton Wanderers / Queens Park Rangers?