Opponents Mainz currently occupy sixth place, the last berth for a place in the Europa League next season, yet Nuremberg are only four points behind in 11th place.
However, Wiesinger is more concerned about what is going on below them in the table and is keen to break through the 40-point barrier before considering anything else.
"I've said it over and over again - we are being absolutely realistic," he said.
"I am not wasting any energy on that (Europe), that would be unnecessary.
"But not looking to Europe does not mean that we are not self-confident, but we have willingly set ourselves the objective of reaching 40 points."
Five points currently separate the Bavarians from that mark, so three against Mainz would leave them six attempts to make the breakthrough.
Easier said than done, though, according to Wiesinger.
"We know that it's hard to play against Mainz," he added at a press conference. "They are very stable away from home and have the ability to change their system during a game.
"We are going to have to be wide awake and alert, ready for a side who will come here with their heads held high."
Mainz coach Thomas Tuchel repaid the compliment and is wary of Nuremberg's strengths at his pre-match press conference.
"They are very dangerous from set pieces and we are going to have to be extremely alert from them," he said.
"They are also very quick on the counter-attack, while they are very compact at the back. It's tremendously difficult to beat them."
Tuchel welcomes a quartet of players back from niggles and ailments to strengthen his side.
"Junior Diaz, Radoslav Zabavnik and Marco Caligiuri are all training again and Zdenek Pospch has a bit of a cold, but we hope he will be fit for Sunday," said Tuchel.