Celtic are reportedly in talks over a £4m transfer move for Mika Baur.
It emerged on Tuesday afternoon that the club had reached an agreement with the player over contract terms.
However, there was not yet a deal in place with the German playmaker's club, Paderborn.
Now, the Daily Record report that Celtic are discussing a transfer fee of around £4m to land the midfielder this summer.
Baur is into the final year of his contract with Paderborn and had been linked with a move to Schalke 04.
Ex-Rangers player Christian Nerlinger is Baur's agent and is reportedly working on ironing out a deal.
The player rep was previously involved alongside Celtic as he operated as Nico Kuhn's agent.
Baur is thought to be keen on a switch to Celtic.
So far, Celtic have only signed Camilo Duran this summer.
The striker has netted in friendlies against Sporting Lisbon and Middlesbrough after making the move to Glasgow from Qarabag.
