Bayern captain Neuer in doubt for crunch Leverkusen clash
Neuer has not trained with the team this week and was only able to complete an individual session on Thursday.
"Manu will try and take part in the goalkeeper training today," Tuchel told reporters.
"It's Manu so we'll give him until Saturday at 5pm to tell us if he's OK."
Bayern face Xabi Alonso's unbeaten Leverkusen, who sit two points ahead of the German champions atop the Bundesliga table, at 17:30 GMT on Saturday.
Neuer returned in October after almost a year on the sidelines with a broken leg.
Tuchel confirmed back-up goalie Sven Ulreich will play if Neuer is unable to.
Bayern are light on goalkeepers, with third-choice Daniel Peretz also out with a knee injury.
Leverkusen have not lost a match in any competition this season, having won 26 and drawn four of 30 games under former Bayern midfielder Alonso.
Tuchel said "30 teams have tried and 30 teams haven't managed to beat them.
"It's an outstanding run and they deserve it. They're doing incredibly well, but we're only two points behind."
"It's still early in the season but it's a clear opportunity for us to lay our cards on the table."
