Ryohei Yamanaka trained with the Japan Rugby World Cup squad for the first time Wednesday in Monaco following his call-up to replace Semisi Masirewa.
Masirewa hobbled off the field in the seventh minute of Sunday's 34-12 defeat to England and was ruled out for the rest of the tournament the following day. The Japan Rugby Football Union did not disclose his exact injury.
Yamanaka, seen by many as unlucky not to have made the original 33-man squad, was in Europe with the British-based Barbarians squad, and flew in to join the team on Monday night.
"I was frustrated when I was not chosen, and the shock was great," the 35-year-old fullback said after the team's gym session.
"I had a feeling that I could go (to the World Cup), and I had been working for it for four years, so I was disappointed. I was depressed for about a week. I couldn't think of anything."
A meeting with former Waseda University teammate Ayumu Goromaru, one of Japan's stars at the 2015 World Cup, helped Yamanaka's mindset.
"I became very positive, and I felt like I still had to work hard," Yamanaka said. "There was also a little alcohol involved."
While talking to Goromaru about the opportunity to play for the Barbarians alongside a number of other players involved in the extended Japan training squad, Yamanaka said he "realized it would be a stimulus."
"If I worked hard, I might have a chance, so I told him I would prepare well."
Playing for the invitation side Barbarians, known for how they enjoy life off the field as well as the exciting brand of rugby they play, allowed Yamanaka to forget about the World Cup and made him "conscious of enjoying rugby and playing for the growth for my next goal."
And while he felt for Masirewa, Yamanaka said now that he was back in the national fold he wanted "to commit to the team and contribute firmly."
The Brave Blossoms, who have won one and lost one, flew back to their base in Toulouse later Wednesday ahead of their crunch game with Samoa on Sept. 28. Their final Pool D game is against Argentina in Nantes on Oct. 8.