Celtic's chances of signing Patrick Roberts ahead of their final Champions League qualifier suffered a major blow when the winger was included in Manchester City's travelling party for a training camp in Catalonia.
Celtic are hoping to re-sign the 20-year-old on loan following a successful 18-month spell in Glasgow and Roberts is believed to be keen on a return.
One of the player's representatives, former St Johnstone and Hearts player Allan Preston, had admitted he expected his immediate future to be resolved last week but City listed Roberts in a 25-man party which landed in Girona on Monday. Nice and Southampton have also been linked with loan bids for the former Fulham player.
Celtic can add one new player to their Champions League squad for Wednesday's play-off first leg against Astana if the signing is registered before 11pm on Tuesday.
Hoops manager Brendan Rodgers revealed on Friday he had also been working on signing a new striker amid fitness issues for Leigh Griffiths and Moussa Dembele.
The latter will miss Wednesday's Parkhead clash with a hamstring injury while Griffiths was only handed a substitute's role in Friday's 1-0 victory over Partick Thistle amid an ongoing calf problem.
Celtic also have a shortage of central defenders. Erik Sviatchenko and Dedryck Boyata are missing with knee injuries and midfielder Nir Bitton was fortunate not to concede a late penalty at Firhill while playing at the back alongside Jozo Simunovic.