Premier League: Romelu Lukaku was on Chelsea's books for three years between 2014 and 2017, but made just 15 appearances as he spent two of those three seasons on loan at West Brom and Everton before joining the latter on a permanent deal.
Euro 2020: French midfielder Paul Pogba played down German defender Antonio Rudiger's apparent attempt to bite Pogba's back during France's tie against Germany.
Chelsea beat Manchester United 3-1 at Wembley on Sunday and will face London rivals Arsenal in the FA Cup final on August 1.
Antonio Rudiger rescued Chelsea as the German defender's second goal of the game earned a 2-2 draw against top-four rivals Leicester on Saturday.
Antonio Rudiger had complained that he was subjected to monkey chants in Chelsea's 2-0 win at Tottenham Hotspur on December 22.
Chelsea's 2-0 Premier League win at the Tottenham Hotspur stadium saw referee Anthony Taylor halt play during the second half when Rudiger complained of hearing monkey noises from spectators.
Antonio Rudiger is Chelsea's second signing of the close season though the first to cost any money. Willy Caballero joined the London giants on a free transfer following his release from rivals Manchester City.