The defender suffered a serious knee injury during the pre-season trip to Spain.
He faces surgery and is out for a significant period.
Head coach Hurzeler revealed to The Argus that Webster suffered a non-contact injury.
It happened in a Saturday morning training session two weeks ago ahead of the friendly against Las Palmas.
Hurzeler said: “It was without any contact. He made the wrong step.
“It just happened. It is very unlucky how it happened but that’s football.
“I don’t want to rule out Adam Webster.
“I think he is a character and he showed in the last season how he always comes back.
“That is why I am quite convinced he will be back as soon as possible.
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“He is a hard worker, he is a grafter, he has a positive mindset and I think this will help in his rehab.
“We will be there for him. “We try to support him in every aspect we can and I am sure he will be back on the pitch as quick as possible.”
Hurzeler has no plans to make a signing to replace Webster in the squad.