"Robin is not in contention to start. He has not played properly for five months," Wenger confirmed. "But he can come in and play a part in the game.
"Robin can produce, even on set-pieces if needed, or the pace drops in the game."
The Arsenal boss, though, played down suggestions he was gambling with van Persie's fitness.
"I don't think now there is any risk, but maybe to start at a high pace and go above your limits, it could be a risk," said Wenger. "Basically his problem at the start it was a thigh problem and a recurrence of it.
"He has really only been able to play eight games this year in the championship (Premier League)."
Arsenal, though, are without defender Kolo Toure, who suffered a calf injury in the first leg on his return from the African Nations Cup.
Wenger remains confident his young squad - who lead the Barclays Premier League - have what it takes to progress to make the last eight of Europe's elite club competition.
"From the result we made in the first game we know we want to attack as well," he said.
"We want to play basically our normal game. It is important to be good on the counter-attack, but, as well, not to drop too deep.
"Of course, we realise we have not to be naive, We want to go from a strong defensive base.
"You have not to defend in your own box as well because players like Inzaghi, Pato, Kaka or Pirlo can hit you if you drop too deep.
"We will need to be disciplined, but as well audacious.
"I will tell you something - tomorrow we do not need anything for motivation.
"The players are focused, are ready for it and will give it their best shot."