|Date of Birth||4 October 1999|
|Place of Birth||Poland|
|Previous club/s||FCB Escola Varsovia|
Marcin joined Chelsea in the summer of 2016 from FCB Escola Varsovia, a Polish academy set up by FC Barcelona (their first such in Europe outside of Spain).
Marcin will pen a professional contract on his seventeenth birthday, to expire at the end of the 2018-19 season.