Valencia left-back Gaya has won 18 caps for Spain after making his international debut in 2018, and he looked likely to deputise for La Roja's vice-captain Jordi Alba in Qatar.

However, Gaya suffered an ankle sprain in training on Wednesday, and while initial reports said his injury was not serious, Luis Enrique has opted against taking any risks ahead of the tournament.

Balde had been preparing to represent Spain's under-21 side against Japan in a friendly on Friday, but he could now win his first senior cap on the grandest stage of all.

Balde made his Barcelona debut in a Champions League defeat to Bayern Munich last September, and has assumed a prominent role in Xavi's new-look team this season.

With Barcelona battling a series of injury problems in defence, Balde has made 16 appearances for the Blaugrana this campaign, starting on 13 occasions.

Spain begins its Group E campaign against Costa Rica at the Al Thumama Stadium on Thursday (AEDT), before taking on Germany in a huge clash four days later.