Spanish superstar Alexia Putellas remains under an injury cloud at the Women's World Cup after failing to make the starting lineup for their opening match against Costa Rica on Friday.

The reigning two-time world player of the year was named on the bench by Jorge Vilda, a day after the coach had said Putellas's fitness was being carefully managed at the tournament.

The 29-year-old hasn't completed a full game since seriously injuring her knee a year ago, forcing her to miss the European Championships in England during 10 months on the sidelines.

Her form before then was good enough to win the Women's Ballon d'Or for a second straight year.

Putellas withdrew from a training session on Monday, adding to lingering injury questions around the attacking midfielder's fitness.

She played the first 60 minutes of warm-up wins over Panama and Denmark, but missed a more recent game, a 9-0 rout of Vietnam.

On Thursday, Vilda said he had a fully fit squad to choose from, before saying of Putellas: "We are very well aware and very careful of everything that we do and we're trying every possible means so that Alexia will be in the condition to play."