It was on Friday that Crewe accepted an improved offer of £300k from the Basque club who is managed by former Fulham boss Chris Coleman.
Coleman told Skysports.com: 'We have finalised a deal for Vaughan with the club and we will speak to the player tomorrow to sort out one small detail, and then he should pass his medical and begin training with his team-mates this Monday.'
Vaughan would of been out of contract next summer and the club decided it was time to cash in, Crewe will be expecting for more money come Friday 24 August as the tribunal of Billy Jones takes place.
Vaughan made his debut back in 200 and went on to make over 200 appearances scoring 20 goals with his best season coming in 2004/05 when he made 48 apperances netting six times.