The pounds 4.5m signing, whose future at Elland Road is in doubt, told Swedish television he was going to play out the season on loan to Norrkoping.
It was meant to be a practical joke, with the Swedish international adding that he hoped to play for another team in Europe next season.
However, the interview was picked up by news agencies and relayed around the world.
Wilkinson said: "I have spoken to Tomas, who gave permission for Swedish TV to conduct an April Fool's interview. He has been surprised by the stir it caused in England."
Wilkinson may now have second thoughts about playing Brolin, who has not been a regular in the team, for the match against Southampton tomorrow.