Chelsea defender Levi Colwill has had surgery on a serious knee injury and is expected to miss most of the season.
The 22-year-old sustained an anterior cruciate ligament (ACL) injury during his first training session after the Club World Cup on Tuesday, and has since had a scan and operation.
ACL injuries typically rule players out for between six and nine months.
Colwill was a near ever-present for Chelsea last season in the Premier League, starting 35 of their 38 matches as they qualified for the Champions League.
The England international also played a major role as a substitute in the Conference League final and during the Club World Cup, as Chelsea won their first two major trophies under the current ownership.