Complex sentence: Jean-Éric Vergne's future at Virgin Racing was in consideration since February and later confirmed to the press on 4 July that he would indeed leave the team, and was later signed to the new Techeetah team three days later.
Split into simpler sentences: Jean-Éric Vergne's future at Virgin Racing was under review since February and it was later confirmed to the press on 4 July that he was leaving the team. He was signed to the new Techeetah team three days later.