Real Madrid made the Welsh winger the most expensive footballer in history when he was signed on Sunday from Tottenham.
Blatter said, "If a player is the value of that, I doubt, I doubt, but I cannot stop this."
The transfer fee was at odds with the economic hardships in Spain, which has been in recession for much of the past four years.
Blatter said, "When you say the country is a poor country or indebted, but in football you always find money ... this is the market and we cannot intervene in this market."
Blatter was speaking on Tuesday at Fifa headquarters in Zurich a day after the European transfer window closed. – Sapa-AP