Signed on a permanent contract after arriving on a short-term basis towards the end of the 2016/17 season.
One of four keepers with the Reserves squad at the training camp in Austria - with Kieran O'Hara, Max Johnstone and Ilias Moutha-Sebtaoui - and likely to push for a place in the Under-23s and UEFA Youth League squad. Formerly with Leeds United, he produced some outstanding performances when thrust into the Reds' Under-18 team to earn a deal over the course of the summer.
Date of birth
United's Champions League debutants Gallery
Mason Greenwood is the 11th Red to make his bow in the Champions League. Can you recall the others..?