Japan captain Wataru Endo racing against the clock to be fit for World Cup opener
The Liverpool midfielder has been struggling with a foot complaint and did not take part in any full training sessions during Japan's warm-up camp in Mexico.
On Monday, after the squad moved to their World Cup base in Nashville, Endo joined his teammates for running and passing drills. Moriyasu stated that the player was still in the running to feature against the Netherlands in Dallas.
"According to the medical reports, there is nothing to indicate that he cannot play," Moriyasu told reporters before departing Mexico. His side also face Sweden and Tunisia in Group F.
"So we simply believe, pray and wait."
Endo sustained a season-ending foot injury while playing for Liverpool against Sunderland in February. He subsequently returned to action for Japan in a 1-0 friendly victory over Iceland in Tokyo on 31 May.
He was substituted at half-time and has continued to experience discomfort.
Moriyasu acknowledged that replacing the 33-year-old in the squad was a possibility if he was unable to contribute during the tournament.
"I am always considering replacements if a player cannot play, and that applies not solely to Endo but to everyone."
"We have several players returning from injury and we must continue to assess them until the very last moment, but we called them up on the assumption they would be fit in time."
Brighton winger Kaoru Mitoma was omitted after suffering a hamstring injury less than a week before Moriyasu announced his squad.
Monaco's Takumi Minamino also missed selection after tearing the anterior cruciate ligament in his left knee in December.