The 25-year old Ivory Coast centre-half joined the Foxes on January 2 for an undisclosed fee but Calderwood indicated that the Edinburgh club did well from the deal.
“Sol's transfer happened very quickly. We had an offer and we came to an agreement with the club,” he told the club’s official website.
"It was an opportunity with the situation - Sol's contract was running down - for a good deal for the club.
"We wish Sol all the very best and we hope he continues to be successful.
"A terrific move for him, but also a good move for ourselves because it was a good bit of business."