Kawasaki Frontale midfielder Kengo Nakamura is still sidelined, though, after breaking his jaw in the Asian Champions League at the end of February, while the Japan Football Association have confirmed Marcus Tulio Tanaka is suspended after being sent off in the defeat by South Korea at the East Asian Championships.

"Because this is not a FIFA matchday, I had to select the players from here and also those who haven't had much playing time," said Okada. "With those players, I am hoping that I can work on possible situations we can have in the World Cup.

"I think Serbia will come with the squad with their domestic players, but they are good in physique and play hard. I look forward to seeing how we can contest against such opponents."

FC Tokyo midfielder Naohiro Ishikawa, Albirex Niigata striker Kisho Yano and Fukuoka University frontman Kensuke Nagai have also been named in the 20-man group for what will be Japan's final outing before Okada's names his 23-man World Cup squad.

"I'm getting my squad in my mind little by little, say 70%," said Okada. "The missing 30% will come from the combinations between the players, whose style goes with whose best, and I will finalise the list on my own."

Japan will tackle South Korea on May 24 in Saitama before a pre-tournament camp in Switzerland in late May.

Okada's side have been drawn in Group E at the World Cup alongside Holland, Cameroon and Denmark, kicking off their campaign against the Africans on June 14.

Japan squad to face Serbia in Osaka on April 7: Seigo Narazaki (Nagoya Grampus), Eiji Kawashima (Kawasaki Frontale); Yuji Nakazawa (Yokohama F. Marinos), Yuichi Komano (Jubilo Iwata), Yasuyuki Konno (FC Tokyo), Yuzo Kurihara (Yokohama F. Marinos), Yuhei Tokunaga (FC Tokyo), Yuto Nagatomo (FC Tokyo), Atsuto Uchida (Kashima Antlers); Shunsuke Nakamura (Yokohama F. Marinos), Junichi Inamoto (Kawasaki Frontale), Yasuhito Endo (Gamba Osaka), Naohiro Ishikawa (FC Tokyo), Yuki Abe (Urawa Reds), Koji Yamase (Yokohama F. Marinos); Keiji Tamada (Nagoya Grampus), Kisho Yano (Albirex Niigata), Shinji Okazaki (Shimizu S-Pulse), Shinzo Koroki (Kashima Antlers), Kensuke Nagai (Fukuoka University).