Career
Youth
From Clifton, New Jersey, Miazga joined the New York Red Bulls Academy in 2009 at under-14 level In 2013, Miazga had signed a letter of intent to play for the Michigan Wolverines men"s soccer program However, prior to arriving in Ann Arbor to play for head man Chaka Daley, Miazga turned down his scholarship offer to play for the Red Bulls at the professional level
New York Red Bulls
On May 30, 2013 it was announced that Miazga had signed a homegrown contract with the New York Red Bulls, becoming the eighth player to sign a homegrown contract with the Red Bulls.
On June 28, 2015 Miazga scored his first goal as a professional in a 3–1 derby victory over New York City Football Club. After strong performances against NYCFC"s David Villa and Toronto Football Club"s Sebastian Giovinco, Miazga became regarded as one of the best defensive players in the league. Chelsea
On January 30, 2016, Miazga joined Premier League club Chelsea on a four-and-a-half-year deal for a reported £3.5 million ($5 million).
Three days later, he was given the number 20 jersey for the remainder of the 2015-2016 campaign. He was first included in a Chelsea matchday squad on February 16, remaining an unused substitute in their 2–1 loss at Paris Saint-Germain in the first leg of the last 16 of the Union of European Football Associations Champions League.
Miazga played one match for the Poland Under-18 team in 2012.
Since 2012, he has played only for United States youth teams. In May 2013, Miazga played for the United States Under-18 side that participated in the 19th Annual International Juniors Tournament in Portugal. In August and September 2014, Miazga turned down two separate call-ups to the Poland Under-20 team
He cited previous commitments to the United States Under-20 team and maintained he had not made a final decision about which nation to represent at the senior level
In October 2014, Poland U-20 coach Marcin Dorna stated that he had not given up on Miazga and that the Red Bulls player might still play for his team Miazga played for the United States Under-20 team at the 2015 CONCACAF U-20 Championship and helped the team qualify for the 2015 Fédération internationale de football association U-20 World Cup in New Zealand.
On November 5, 2015, Miazga was quoted as saying: "I"m totally undecided.