Cropper joined the Clarets as a first-year scholar in February 2017.
Initially, signing as a forward player, the former Ilkeston Town youngster successfully switched to a right-back role with a dangerous long throw.
A regular in the Under-18s, Cropper hit the winning goal at Turf Moor against Leeds United in the FA Youth Cup in January, 2018.
The defender was then handed a third-year scholarship contract at the end of the 2018/19 season.
After an impressive season in the Under-23s, Cropper was then rewarded with a first professional contract in June, 2019.
Cropper then signed for National League side Chesterfield on loan until the end of the season, in January 2020.
The right-back then returned to the Clarets, after the football league season was cut short due to the Covid-19 pandemic, but rejoined Chesterfield on loan in August 2020 for the season.