Celtic are considering a move for Arsenal left-back Kieran Tierney next month.
Sky Sports News understands the Hoops are exploring a pre-contract and loan offer for the Scotland international.
Arsenal are expected to listen to offers for Tierney in the January transfer window, with the club not expected to trigger the one-year contract extension in his current deal.
There is currently no agreement on a new contract for current Celtic left-back Greg Taylor, with his deal due to expire in the summer.
Celtic also have Barcelona left-back Alex Valle on a season-long loan deal.
A number of clubs across Europe are also said to be interested in Tierney, who Arsenal from Celtic in 2019 in a deal worth around £25m.