The England international last played at a World Cup in 2006 and has seen his chances of traveling to Russia this year severely hampered after failing to start a single Premier League match.
Everton have since offered Walcott a shot at regular first-team football after opening discussions with the Gunners over a January deal for the 28-year-old, and while Wenger is keen to retain the striker's services, he admits the situation is a delicate one.
When asked he if he could give the player any assurances about game time, the manager said: "No, you just cannot do it, because it is not honest.
"We will see. We have a good relationship still and I don't want him to be frustrated or to lose an opportunity to go to the World Cup.
"Theo went to the World Cup in Germany in 2006 and we are now in 2018, and he has not been since [back to the World Cup], for different reasons."