Vasilis Barkas goes straight into the Celtic squad for the Ladbrokes Premiership opener against Hamilton on Sunday.
The 26-year-old goalkeeper, who has been capped 10 times by Greece, joined the Scottish champions on a four-year deal from AEK Athens on Thursday and his fitness will be assessed by Neil Lennon.
Winger Mikey Johnston will have surgery on a calf problem which will keep him out for four to six weeks.
Hamilton have added Hakeem Odoffin to their squad after signing the defender from Livingston.
Ross Callachan, Callum Smith, Charlie Trafford and Tunde Owolabi are also available to make their debuts.
Club captain Brian Easton is out until October following ankle surgery and Will Collar until September with shin problems, while David Templeton is back training following a back problem but the game comes too soon.
Manchester City in eye-watering bid for Barcelona star Raphinha: report
'I begged Newcastle to sign Zidane. Kevin Keegan told me his chief scout thought he wasn’t good enough - years later, he told me he should have listened to me instead': The incredible story of how Newcastle United REJECTED Zinedine Zidane for just £1.2m
