Concerns are mounting over the fitness of Spain forward Nico Williams after he was forced off with an apparent hamstring injury during Athletic Bilbao's 1-0 home defeat to Valencia on Sunday. The 23-year-old, a key figure in Spain's attacking lineup, was substituted in the 37th minute at San Mamés stadium, with his brother Iñaki Williams taking his place on the pitch.

This latest setback comes at a particularly worrying time, just ahead of the World Cup, and follows an earlier injury that sidelined Nico for several weeks earlier this year. Athletic Bilbao have not yet released details on the severity of Sunday's issue, but his brother's comments have done little to ease fears.

"He was limping a lot. He hadn't felt that type of pain before," Iñaki Williams said after the match. "It's concerning considering the moment we are right now. Let's wait and hope for the best possible scenario."

Nico Williams has been a regular fixture in Spain's national team, forming a dynamic attacking partnership with Barcelona's Lamine Yamal—who is also currently nursing an injury. The timing couldn't be more critical, as Spain coach Luis de La Fuente is set to announce a 55-man preliminary World Cup squad on Monday.

For fans and followers of the game, this is a developing story that could have major implications for Spain's World Cup campaign. Stay tuned for updates as we learn more about Williams' condition and how it might affect both his club and country in the weeks ahead.