Albion have reached an agreement with the FA that will ensure Ashworth remains the club's sporting and technical director until June before taking on a similar position with the FA, where he will be charged with overseeing the future of English football.
Negotiations between the FA and Albion are at an advanced stage and Ashworth is believed to have received assurances about the post before deciding to accept the role at the new centre in Burton-upon-Trent.
The job title is still uncertain but Ashworth will have a major say in the coaching and development of youth players, effectively taking on a similar position to Dave Brailsford with British Cycling.
An official announcement is expected to be made by the FA later this week but Ashworth will not begin his new job until he has served his notice period at the Hawthorns, which expires at the end of the current campaign.
The FA are keen to have the 41-year-old in place within weeks but Albion chairman Jeremy Peace, a renowned tough negotiator, has successfully agreed a compromise. Peace is understood to have made it clear that Ashworth had to remain at the club for the January transfer window.
It is understood he sought guarantees from the FA about the exact definition of the role, and how much overall control he will have, before agreeing to take on the position which will more than double his current £200,000 a year salary.
A former Norwich City player, Ashworth first established his reputation at Albion's Academy after working in similar roles at Peterborough and Cambridge. He was promoted to technical director in December 2007 and is largely responsible for player recruitment, the Academy and sports science.
His record in the transfer market has been particularly successful in recent years, bringing the likes of Peter Odemwingie, Youssouf Mulumbu and Claudio Yacob to the club for minimal fees. Earlier this year he travelled to Argentina to watch Yacob train for his club Racing, clambering over a fence to get a better look at a player he eventually signed on a free transfer.
Ashworth's departure will be the second major exit from Albion this year, after Roy Hodgson left to take charge of the England national team in May. Hodgson is believed to have been a key figure in the appointment, though Ashworth is more likely to liaise with Trevor Brooking, the FA's director of football development.