On 21 December 2007, it was announced that León had signed a pre-contract agreement with Barnsley, with the transfer due to go through at the opening of the transfer window. The Yorkshire club had hoped to make the move official in time for him to play in the FA Cup third-round tie against Blackpool on 5 January 2008, but had to wait until the 9th: he made his first appearance that evening, playing in a reserve team match against Sheffield United.