Neuer is set to play his first full game since fracturing his foot last September, on Saturday away to Austria in Germany's penultimate friendly before the World Cup.
After such a lengthy absence, the 32-year-old who is generally regarded as one of the world's top goalkeepers is under pressure to prove his form and fitness.
"The final decision will probably not come until Sunday night," said Germany's head coach Löw on Friday.
"For the moment everything is on plan for Manuel Neuer.
"I'll talk to him tonight and if everything is okay, he'll play against Austria."
Löw has said he will only take Neuer to Russia as his first-choice 'keeper.
Barcelona's Marc-Andre Ter Stegen has deputised for Neuer, who has not played for Germany since October 2016.
Despite months on the sidelines, the Bayern Munich star has impressed in practice games at Germany's World Cup training camp in Eppan, north Italy.
Neuer pulled of a string of saves earlier this week when he helped the Germany Under-20 team restrict their margin of defeat to the senior team to just 2-0. He was only beaten by a Thomas Mueller penalty and a Julian Draxler goal.
Löw is set to leave several World Cup winners out of the team for the friendly in Klagenfurt.
Defender Jerome Boateng, who has a groin strain, and midfielder Toni Kroos, who was rested winning the Champions League with Real Madrid last weekend, will sit out.
Mats Hummels and Thomas Mueller, who are rested, are also being left behind in Eppan by Löw, but for the rest of the 27-man squad this is their last chance to win a place on the plane to Russia.
"I'm planning to use all my substitutions against Austria," added Löw, with a maximum six permitted.
"The Under-20 team was a welcome sparring partner, but Austria will be an important friendly and the result will be just a minor matter.
"In this phase, it is important to gain some knowledge and see some processes which we have worked on.
"They will demand a lot from us. "
Whether or not he includes Neuer, Löw said he knows he still has to disappoint "burst some World Cup dreams".
Four names must be cut before the final 23-man World Cup team is submitted to FIFA on Monday and Löw said decisions will only be made "late on Sunday night".
"On Monday morning, I will speak to the relevant players and they will leave the squad around midday," said Löw.
"When I call their room, they will already have a bad feeling as I won't be calling the likes of Jerome Boateng, Mats Hummels or Joshua Kimmich."
The German federation were left red-faced this week when a poster appeared on their website showing how their squads' names appear in sign-language, minus defender Jonathan Tah, midfielder Sebastian Rudy, goalkeeper Kevin Trapp and striker Nils Petersen.
Team director Oliver Bierhoff insisted the slip-up does not reflect the quartet set to miss out on a place at Russia.
Germany play their final friendly before Russia 2018 when they host Saudi Arabia in Leverkusen next Friday with their opening World Cup match against Mexico in Moscow on June 17 having also drawn South Korea and Sweden in Group F.