The 30-year-old’s last appearance for Hearts came on January 11 last year in the Scottish Cup fourth round defeat by St Johnstone.
“It’s a big problem and I don’t know what is the point right now,” admitted Sergio. “We have different opinions. One says he should get more surgery, then comes another saying he shouldn’t. It’s a big problem with his hip.”
Asked if he was concerned that Kyle’s career could be finished, Sergio replied: “Maybe.”
The Portuguese also admitted he is unclear over exactly when Rudi Skacel becomes a free agent, with the player expected to leave Hearts in the coming weeks.