Iniesta doubtful for Spain opener
The Barcelona playmaker asked to be substituted in the first half of their 6-0 warm up win over Poland in Murcia, Spain on Tuesday, with the coaching staff saying that it was simply a precautionary measure.
"He has a small oedema (fluid swelling) in his right thigh. It is not a serious injury and there is no tear," the federation said on their website.
"There isn't a fixed recovery period so he is not ruled out of the first game of the World Cup in South Africa, which takes place against Switzerland in Durban on June 16."
Iniesta has struggled with a string of thigh problems over the last year and has just returned to action after missing the end of the league season.
He has played in all three of Spain's warm-up matches and was in outstanding form against Poland, helping to set up Spain's first two goals before being replaced by Pedro.
The European champions, who travel to South Africa on Thursday, are in Group H with Switzerland, Honduras and Chile.