Former Hearts manager Craig Levein says Celtic have tried to re-sign Aaron Hickey on "five or six" occasions.
The left-back spent time in the Parkhead youth academy, and has been linked with a return since breaking into Hearts first team.
And Levein says Celtic have made numerous attempts to bring the defender back, amid rumours of his exit this summer.
He said on BBC Radio Scotland: "Celtic tried to buy him back half-a-dozen times and that just got knocked back.
"Celtic tried to buy him back while he was in the first team, I think it was five or six times."
The youngster has plenty of suitors this summer, with Record Sport revealing that Bologna are leading the race for his signature.
Sky Italia reports that he's already been shown around the Serie A club's training ground, with the Rossoblu awaiting a response from Hickey.
Aston Villa are also keen on Hickey after securing their Premier League status, with Bayern Munich interested too.
However, the Italians could offer the 18-year-old first team football right away which could prove appealing.
With a year left on Hickey's contract, they're prepared to pay around £1.5million to secure his services.
Sporting director Walter Sabatini has confirmed they're on the lookout for a full-back.
He said: "I agree with the analysis of (Sinisa) Mihajlovic, a full-back, a centre-back and a striker weren't heat-of-the-moment requests from the coach.
"Our vision is also shared from a financial point of view, we won't be able to go overboard but we'll do the maximum we can."
