Lorenzo Sassi, a prominent member of Scuderia Ferrari's engine department until last summer, has been recruited by Mercedes.
The team's chief engine designer was ousted last July on direct order from Ferrari boss Sergio Marchionne, a move which came as a surprise given the progress of Ferrari's power unit at the outset of 2017.
It was believed at the time that the Italian engine would remain within the Fiat Chrysler group, but Sassi was apparently reluctant to work outside of F1.
According to Spanish newspapers AS and Marca, Sassi is on his way to Mercedes AMG F1's engine headquarters in Brixworth.
Sassi isn't the first high profile Ferrari engineer to switch to Mercedes, the German squad having enrolled in the recent past designers Also Costa and James Allison.