BT Sport changed plans for the pair to attend Ibrox ahead of Rangers' Europa League clash against Lyon.
The Croatia right-back sought advice from the former Celtic goalkeeper.
Celtic forward Kyogo Furuhashi has been targeted by fans travelling to the Highlands.
Ralston only played one game last season but has been ever-present since Postecoglou’s arrival amid a dearth of alternative right-backs.
Celtic have agreed a fee with Polish side Legia Warsaw.
Celtic go into Wednesday’s play-off first leg at Parkhead on the back of netting 16 goals in four games.
There will be no away section at the game in Glasgow on Sunday.
The former England goalkeeper could make his Celtic debut in Czech Republic.
Carl Starfelt and Kyogo Furuhashi made their debuts in the 2-1 defeat to Hearts.
The outgoing defender hailed Kennedy as the 'most important' person at the club.
The 26-year-old winger joins the Hoops from J1-League club Vissel Kobe on a four-year-deal.
Ajeti is looking to make up for a trophyless first season at Celtic.
A fee has been agreed for the Swedish defender.
Cars were targeted in the blast at the former Celtic chief executive's home in Thorntonhall in May.
The 30-year-old will be out of contract at the end of this month.
Shaw signed a pre-contract agreement in March.
All fixtures for the Premiership season ahead have been revealed.
Great goals, underdog stories, drama, excitement and heartache - it must be time for the Euros.
The Celtic centre-back has just finished a loan spell with Belgian club KV Oostende.
The outgoing Celtic chief also thanked the emergency services for how they dealt with the incident.