Manager Gordon Strachan has yet to inform defender Seweryn Gancarczyk if he has won a move to Celtic.
Gancarczyk has been training with Celtic this week
The Poland international has been training with the Scottish champions at rain-soaked Lennoxtown this week.
"He can see our style and see whether he wants to live in the pouring rain, sleet and wind for the next three years," joked Strachan.
"But I will be speaking to Seweryn later on, it would be unfair to speak to the media first then him."
Left-back Gancarczyk is rated at £750,000 and has played most of his career in Ukraine with Metalist Kharkiv.
Celtic also invited American international goalkeeper Brad Guzan to their training headquarters.
Guzan, 23, is valued at about £1m and has played four times for the USA.
Strachan dismissed reports that Portsmouth want left-back Lee Naylor, saying Burnley's failed attempt to land Derek Riordan for £400,000 has been the only concrete bid received.
He said: "The only direct offer was for Derek Riordan.
"That is not going to happen for that price and it is not going to happen because I trusted him to play in an emergency last week and he did well."