A youthful selection failed to impress in a dour goalless draw against Poland earlier this month, with a host of players absent due to club commitments.
Low must name his final 23-man party for Brazil by Monday - meaning the friendly with Cameroon offers a final chance for fringe players to tie down their place in the squad.
"It is an important opportunity for me once again to gain knowledge, both tactically and on individual players," he said on Friday.
"We will decide who will be in the final 23 to go to Brazil on Sunday after the game."
With Neuer out of Sunday's game, Borussia Dortmund's Roman Weidenfeller is likely to step in for what would be only his second cap.
"For me it is a great honour and opportunity. I have never experienced (the World Cup) and at (the) age (of) 33 to experience a World Cup is priceless," he explained.
"I hope I can experience it to the very end and maybe even hold the cup in my hands."
Sunday's fixture represents a third game of the week for Volker Finke's men as they step up their own preparations for the World Cup.
