McManus will deputise for regular skipper Darren Fletcher, who is one of 10 players called up for manager George Burley's original 22-man squad for the Kirin Cup match against Takeshi Okada's side to have pulled out of the game.
The lack of many of Scotland's biggest names - including Fletcher, Shaun Maloney and Scott Brown - has proven controversial at both home and in Japan, but McManus is focusing on the young players who have been called up for the clash with the three-time Asian champions.
"There have been a lot of injuries and there's not a lot we can do about that but some of the lads are going to get their first caps, which is great," said the 27-year-old.
"It's a young squad and there's not a lot can be done about that. We're looking forward to the game.
"It's my first time to be in this country and we are just looking forward to the game. We have come a long way to be here."
Fletcher along with Tottenham defender Alan Hutton, Brown, Maloney, Danny Fox, Kevin Thomson, Steven Naismith, Robert Snodgrass and Garry O'Connor were among those to withdraw from the game against a Japanese side that has already qualified for the World Cup.
But as Japan prepare to play in their fourth finals in a row, Scotland are looking at rebuilding and refocusing for the qualifiers for the 2012 European championships in Poland and Ukraine.
Burley has also been forced to travel to Japan without James McFadden, Ross McCormack, Chris Iwelumo, Kenny Miller, James Morrison, Kris Commons and Gary Naysmith, none of whom were named in the original squad.
However, the absence of the senior players has allowed Burley to select a band of younger hopefuls who will be out to prove to the former Ipswich and Southampton manager that they are good enough to play at international level.
At least three players are expected to make their debuts for Scotland, with Graham Dorrans of West Brom, Lee Wallace from Hearts and Preston midfielder Ross Wallace all likely to start.
In addition to that trio, Don Cowie and Stephen Hughes of Watford and Norwich City respectively were late call-ups and may feature at some stage against a Japan side that is likely to be completely different to the one that defeated Hong Kong 6-0 in an Asian Cup qualifier on Thursday.
Okada chose to field a full strength squad against the former British colony after learning Scotland would be bringing a weakened side, but he is still likely to hand a debut to Serie A-based striker Takayuki Morimoto.
The 21-year-old, who plays his club football for Catania, sprung to fame in Japan when he became the youngest player to score in the J.League when he netted for Tokyo Verdy against JEF United Ichihara just two days before his 16th birthday.