Defender Tulio has declared himself fit for Japan's last 16 clash with Paraguay in Pretoria on Tuesday after recovering from a knock, although coach Takeshi Okada may be tempted to name the same XI that beat Denmark 3-1.
Paraguay midfielder Victor Caceres is suspended but Antolin Alcaraz could return after missing the goalless draw with New Zealand due to a minor injury.
La Albirroja coach Gerardo Martino has highlighted Japan's rapid counter-attacks and dead-ball prowess as two areas his side will need to address if they are to progress to the quarter-finals of the World Cup.
Paraguay were surprise winners of Group F following the shock demise of defending champions Italy and the South American outfit are now one game away from a first-ever place in the last eight.
Looking at the threats Japan could pose his side, Martino said: "Fundamentally they are a team who get back into their defensive positions very well, using a back-line of four and practically five midfielders, with (Keisuke) Honda generally up front.
"When they get the ball they come out very quickly on the counter-attack, this is what we have to be careful of most, the fast breaks. When they find space they get men forward into attack and this is the most important issue to be careful about."
Shinji Okazaki has warned Paraguay that Japan have "nothing to lose" as they bid for a historic place in the quarter-finals.
The Blue Samurai put poor form in the build up to the tournament behind them with victories over Cameroon and Denmark in Group E to seal their place in the last 16 for the first time on foreign soil.
"We didn't have a South American team in our group and I expect there will be fiercer tackling for the ball and the most important thing is that we don't lose those battles," Okazaki said.
"We have been winning those battles and that is how we have got this far. If we stay confident then I think we can keep winning. We have got nothing to lose."