On 15 March 2011, São Paulo announced that Piazon could only play for the Chelsea senior team after 20 January 2012 when he became eligible to obtain a work visa, but he would join in the 2011 summer transfer window. Chelsea announced ten days later with Piazon passing a medical in London in early March 2011. It was reported that Chelsea paid in the region of £5 million to acquire Piazon, which could rise to £10 million depending on several clauses. He was transferred to Chelsea during the 2011 summer transfer window and started playing for the reserves. In an interview, he stated, "[I chose Chelsea because] I like the Premier League. I think my way of playing and my skills are more suited to the Premier League." Piazon made his debut for the reserve team against Fulham, thereafter saying, "I am able to play in the Youth Cup now. Everybody knows I am here to play, so my main aims for the season are to play as many youth games as possible and hopefully feature in the reserves as well, and I want to win the Youth Cup." He also stated, "I am enjoying the company of Ramires, Alex and, of course, David Luiz is my best friend here. He is so funny and always joking so it's nice." Piazon scored his first reserve goal in an away victory against Arsenal, just before full-time with a solo effort, inside the box before firing it into the net. He has scored twice in five games for the reserves and once in six for the youth team, most notably the winner in the FA Youth Cup tie against Doncaster Rovers. He won the FA Youth Cup on 9 May 2012 against Blackburn, although failing to score in the match. On 20 January 2012, his 18th birthday, Piazon obtained a work visa and became eligible to play for the Chelsea senior team. On 26 January 2012, he signed a contract extension that will keep him with the club until 2017. After impressing at Under-18 and Reserve level, Piazon was given the number 35 shirt, which was previously worn by Juliano Belletti. He was an unused substitute on the Chelsea bench, on 31 January 2012, in their 1–1 league draw against Swansea City and on 5 February 2012, in the 3–3 draw against Manchester United. Chelsea manager André Villas-Boas said, after the Manchester United game, "He [Piazon] has trained more with the first team, which is very good for him.