The 41-year-old has stepped down as the Baggies' technical director after nine years in the job in order to succeed Gareth Southgate as head of elite development
The 41-year-old, who had spent nine years with the Baggies in a number of different capacities, announced in September that he would leave the club in the summer.
With his replacement Richard Garlick already in place at the Hawthorns, however, Ashworth has opted to make an early departure in order to succeed Gareth Southgate.
And the former Norwich defender had nothing but praise for the club, whilst also insisting he will not be missed for the remainder of the season.
He told the club's official website: “I have had nine fantastic years here and I just want to say a big thank to everyone connected with the football club – the staff, players and supporters.
“With the January transfer window now closed, the team having already amassed 40 points and Richard very much hands on in his new role, we all agreed that this would be an appropriate time for me to move on.”
Baggies chairman Jeremy Peace also thanked Ashworth for his hard work, saying: “Dan has worked tirelessly for this football club for the past nine years and leaves with our best wishes.
“He has remained fully committed to his club responsibilities since it was announced last September he would be leaving, for which I would like to thank him.
"The handover with Richard has gone extremely well, which has enabled us to agree to an early departure date with the FA for Dan, and we now look forward to Richard building on the solid foundations laid by Dan.”