Jordan technical director Mark Smith has quit the Formula One team following their takeover by Midland last week.
A Jordan spokeswoman said the former chief designer at Renault, who only moved to the team last month, had left for personal reasons.
Jordan are rushing to complete their car before the start of the season in Australia on 6 March.
But the takeover by Russian-born businessman Alex Shnaider has created a measure of upheaval.
Smith is a friend of Toyota technical director Mike Gascoyne and there was speculation when he returned to Jordan that it would just be a stop-gap before a move to Toyota.
Smith worked for Jordan for many years before switching to Renault to join Gascoyne in 2000.