Marshall suffered the injury after impressing in Redcliffe's 28-20 win over Ipswich, having scored one try and had a hand in three others.
"It is really unlucky for it to happen like this but that is football," Marshall told broncos.com.au
"All I can do now is concentrate on it getting better and keep training for a return as soon as I am able."
Read more at broncos.com.au