Japan's mindset will not change if Colombia are without star playmaker James Rodriguez for their World Cup opener, defender Yuto Nagatomo said Saturday, following reports the 2014 Golden Boot winner is a doubt for the Group H clash in Saransk.

Multiple outlets have reported that 26-year-old Rodriguez, the man-of-the-match in Colombia's 4-1 rout of Japan at the 2014 World Cup, could miss next Tuesday's match due to problems with his left calf.

Rodriguez, who is usually deployed by La Tricolor as a roaming attacker, trained separately from the squad Thursday and was absent from practice a day later.

Currently on loan with Bayern Munich from Real Madrid, Rodriguez missed two weeks of the Bundesliga season earlier this year with calf problems, although it is not clear whether the current issue is related.

But Nagatomo, who is currently on loan with Galatasaray from Serie A giants Inter Milan, said, "Nothing changes. Whether (Rodriguez) plays or not, no matter who lines up for our opponents, the way we approach the game doesn't change."

The 31-year-old, who is the subject of negotiations between Inter and Galatasaray for a permanent move to Turkey, added, "The team and coach (Akira) Nishino have a strategy in place that doesn't depend on whether a certain player is or isn't in the opposing lineup."

Nevertheless, if two-time Champions League winner Rodriguez were to miss the match, it would be a welcome development for the Samurai Blue, according to midfielder Genki Haraguchi.

"He's their key player, so from our point of view, if he's not playing, it makes things easier," said the 27-year-old, who completed a deal in the offseason to join Bundesliga side Hannover.

Japan, meanwhile, face fitness concerns with a key player of their own, with Leicester City forward Shinji Okazaki unable to train with the squad for a third straight day due to soreness in his right calf.

After playing the first 74 minutes of Japan's 4-2 friendly win over Paraguay on Tuesday, Okazaki skipped the first day of camp in Kazan two days later with tightness in his right thigh and both calves.

The 32-year-old practiced separately from the rest of the Japan squad the following day, doing light running drills one-on-one with a trainer.

Kawasaki Frontale midfielder Ryota Oshima and Kashima Antlers defender Gen Shoji ran with the rest of the squad Saturday after training separately the previous day due to right thigh and left hamstring issues, respectively.