Young, Smalling back to boost Man Utd boss Moyes
Kagawa was always due to link up with his team-mates for the Japan leg of the five-match tour after being given an extended break due to his Confederations Cup campaign.
However, Young and Smalling have been battling to overcome ankle and foot injuries respectively.
Both have been deemed fit enough to join the tour and flew into Tokyo today before meeting up with their team-mates in Yokohama, where they will face the local J. League side, Yokohama F Marinos, on Tuesday.