Chelsea defender Levi Colwill has been surgery on a serious knee injury and is expected to miss most of the season.
The 22 -year -old suffered an anterior cruciate ligament (ACL) injury during his first training session after the club’s World Cup on Tuesday, and since then he had a scan and operation.
ACL injuries usually dominate players between six to nine months.
Colwill was close to Chelsea last season in the Premier League, starting 35 of the 38 matches when they graduated in the Champions League.
England also played a major role as an alternative to the conference finals and during the club’s World Cup, while Chelsea won their two major kidnappings under current ownership.
Asked if Chelsea need to sign another defender to replace Colwill in his media conference before friends against Bayer Leverkusen and AC Milan, Maresca said: “It depends – we’ll wait and see.
“You know in our way, Levi has been very important. I talked to him yesterday and told him that if we achieved what we achieved last year, it is also because of him – and he was a great player for us.”
Chelsea defensive options are signing new Jorrel Hato, Tosin Adarabiio, Benoit Badiashile, Trevoh Chalobah and Josh Acheampong.