Luis Aragones has injury doubts over Carles Puyol and David Silva ahead of Saturday's Euro 2008 qualifier against Denmark.
Puyol, who has only recently returned from a knee injury, suffered a minor calf strain in Barcelona's 2-0 UEFA Champions League win over Stuttgart last week.
Silva, meanwhile, is feeling the effects of an ever-present start for Valencia this season and is struggling with muscular pain.
Uncapped Valencia defender Raul Abidol is in line to replace Puyol, while Arsenal's Cesc Fabregas is likely to join a midfield of David Albelda, Xavi and Joaquin if Silva fails to shake off his injury.
In a bid to try out the effectiveness of Abidol and Fabregas, Aragones utilised the duo in a potential starting XI in training on Thursday.
Spain have amassed 19 points so far and sit second in Group F - with Sweden leading the way on goal difference.