The 31-year-old grumbled that he needed to "think about stuff" after being left out of Espanyol's La Liga match against Almeria at the weekend.
However, Nakamura sought to allay concerns he was about to walk out on the club just months after arriving to a "Galactico" billing and comparisons to Cristiano Ronaldo.
"I didn't mean it that way," Nakamura told Wednesday's Japanese media after his arrival from Spain for the Christmas break.
"I meant I have to think about how to play more games."
Nakamura joined Espanyol on a two-year deal from Scotland's Celtic in June after winning three Scottish Premier League titles at Parkhead.
However, he has struggled to establish himself at the Barcelona-based side and his form for Japan has also suffered a dip with the 2010 World Cup less than six months away.
"I'm not over the moon about things," Nakamura told the Nikkan Sports. "But it's a question of trial and error."
He added: "Everything went so well during my four years at Celtic so it's a good experience to have to worry sometimes.
"People might get concerned I could lose my match sharpness before the World Cup but I'm not done yet!"
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