Jack Collison has had a knee cartilage operation and will be out of action for around nine months.
The Wales midfielder has not played since the 3-0 defeat at Manchester United in February because of the injury. He has undergone surgery and, having begun his rehabiltation, will hope to return as soon as he can in the new campaign. He joins Zavon Hines on the long-term injured list, with the new Young Hammer of the Year hoping to be back in pre-season.
Gianfranco Zola said: "Jack had an operation the other day. He is going to be out for nine months. We hope he comes back quicker than that. I know he is a strong fellow and will do his best. I am sure it is a difficult time for him."
Herita Ilunga and Kieron Dyer are also expected to figure fully from July after muscle problems respectively, while Valon Behrami has a knee knock and will miss the last game of the season. The manager could consider James Tomkins and Luis Boa Morte for Sunday's visit of Manchester City after both came through the midweek Tony Carr testimonial.