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.
When asked if Chelsea needed to sign another defender to replace Colwill at his media conference before friendlies against Bayer Leverkusen and AC Milan, Maresca said: “It depends – we will wait and see.
“You know in our way, how important Levi has been. I spoke with him yesterday and I told him that if we achieve what we achieved last year, it is also because of him – and he was a main player for us.”
Chelsea’s alternative defensive options are new signing Jorrel Hato, Tosin Adarabioyo, Benoit Badiashile, Trevoh Chalobah and Josh Acheampong.
