Playmaker David Silva trained separately from his Spain team-mates on the eve of the international friendly against England, casting doubt on the Manchester City star's involvement at Wembley.
Julen Lopetegui's squad worked with the ball at their open session ahead of Tuesday's match in London, with the exception of Silva, who went through a series of exercises along with a member of Spain's backroom team.
The Manchester City playmaker completed 90 minutes and captained the side as La Roja beat Macedonia 4-0 in Saturday's World Cup qualifier and Lopetegui did not report any specific injury concerns at his pre-match news conference.
"We're going to see tomorrow," he said. "We've got another 24 hours and we're going to see how everybody is.
"We have an idea roughly but we'll see what the exact scenario is tomorrow, how we're going to set up and who's going to feature.
"The first people to know of any changes will be the players themselves, of course, and they'll know when we announce the team tomorrow night."
Spain's players get to work with the ball, apart from David Silva, who is working alone with a fitness coach on the far side of the field. pic.twitter.com/cPwodPqlUr-- Dom Farrell (@DomFarrell1986) November 14, 2016
Silva has won 105 caps for his country, scoring 28 times, and the 30-year-old has continued to feature prominently under Pep Guardiola this season for City, who are back in Premier League action at Crystal Palace on Saturday.