He was a key member of the Scotland Under-20s squad which finished third in the Toulon Tournament this summer.
Scot Gemmill could hand him his Under-21s debut next week after naming him in the group for next week’s Euro qualifier against Holland.
West Ham are thought to have sent scouts to monitor the 18-year-old.
Ralston is under contract at Parkhead until 2019 – was given his debut Hoops by boss Brendan Rodgers in the 2-1 win over St Johnstone in May. Rodgers has since used him in four games this term.
He was a key member of the Scotland Under-20s squad which finished third in the Toulon Tournament this summer.
Scot Gemmill could hand him his Under-21s debut next week after naming him in the group for next week’s Euro qualifier against Holland.