Lotus technical director James Allison, one of the most highly regarded design engineers in F1, is to leave the team.
Lotus are expected to imminently announce Allison’s departure, and his replacement by Nick Chester.
It is not known which team Allison is joining, but Ferrari are strong favourites.
Allison has had an offer from McLaren, which he is understood to have turned down, and has also been approached by Williams and Mercedes.
His departure is a blow to Lotus, whose driver Kimi Raikkonen is second in the world championship to Red Bull’s Sebastian Vettel, ahead of the fifth race of the season in Spain this weekend.
Allison’s future has been the subject of fevered speculation in F1 for some weeks.
He has been linked to all the top teams – Red Bull, McLaren, Ferrari and Mercedes – as well as Williams.
But a Red Bull source dismissed the notion that Allison would be joining them and BBC Sport understands Allison has rejected an offer from McLaren.
Mercedes motorsport director Toto Wolff told BBC Sport that Allison had been approached by the team’s non-executive director during the winter but that it was “historical” and appeared to rule out his appointment.
Mercedes have already signed former McLaren technical director Paddy Lowe, who will join the team in 2014 in a senior technical role overseeing the team’s current structure.
If Allison does move to Ferrari, it is unclear what role he would take – the team’s technical director Pat Fry has been in his role for less than two years.
Fry and Allison have previously been colleagues, at the Benetton team in the 1990s.
Allison worked at Ferrari for five years from 2000, the period during which they dominated F1 with Michael Schumacher, before moving back to Renault – which was renamed Lotus in 2012 – in 2005 as deputy technical director.
He was in that role as Fernando Alonso won his two titles for the team in 2005-6 and was promoted to technical director in 2009.