Mara has impressed in brief spells in the top grade but has received limited opportunities, playing just 10 matches since making his debut in late 2010.
The 22-year-old Wellingtonian looked to be in good shape during pre-season trials but has battled injury for much of the period since.
He returned for the Vulcans last week and came through Saturday's 18-32 loss to Balmain-Ryde unscathed.
While Mara provides a specialist hooking option, Brown might well prove the primary back-up at dummy-half.
Having begun his career as a hooker who never quite made the grade at the Roosters, the Penrith-bound Brown has played most of his first grade and test football in the back row or as a makeshift centre.
Sharpening up his hooking skills has been a focus for Brown under coach McClennan. He certainly provides a powerful dummy-half running option and scoring threat close to the line, but his distribution isn't a strength.
Brown would have received more game time at hooker this season but for Friend's tireless work rate in defence in the middle of the park - something the Warriors must now replace.
"Friendy has been holding up that middle very well for us so we haven't had the chance to use [Brown] there that often.
"But he has been doing a lot of work in training in the dummy half area," McClennan said.
"Him and Ale are our first ports of call."
Friend's absence would also see the team's props receive more game time in an attempt to spread the workload, McClennan said.
Captain Simon Mannering also departed early on Saturday night, but his medial knee strain isn't expected to be a serious issue and he will likely take his place against the Roosters on Saturday night.
Forward Steve Rapira is expected to be available, while brother Sam (ankle) and fullback Kevin Locke are outside chances of a return.
