The Danish striker surprisingly joined Championship club Nottingham Forest earlier this month after experiencing a downturn in form following a bright start to his career with the Gunners.
Wenger admitted it was a shock to see the 28-year-old former Birmingham City, Sunderland, Juventus and Wolfsburg forward make his way to Forest but is confident he has the ability to rediscover his best if given the chance to play regularly.
"It was a surprise to me that Nicklas signed for Nottingham Forest, but at some stage Nicklas needs to restart his career," he said ahead of the EFL Cup clash between Arsenal and Forest on Tuesday night.
"You have to adapt and we are in a job when we have to show we are able to put our effort in everywhere and compete.
"Sometimes when you are a player of his quality, you just need an opportunity. We know his qualities and he is a top-quality player, but he needs to play."
He added: "Of course he has a point to prove.
"Nicklas is humble enough and focused enough to show he can fight again."