Fletcher began training with the first team when Erik ten Hag was still manager, and was called into his first matchday squad under the Dutchman for the game against Brentford on October 2024. He continued to feature among the substitutes when Ruben Amorim became coach, and got his big chance in December 2025 when he was brought on in the second half at Aston Villa, becoming the club's 255th academy graduate.
He could not help United find a way back into the game as they lost 2-1, but it was a huge moment for him and his family as the Fletchers became the first father and son duo to both play for United in 60 years.
When Mason Mount pulled up injured at half-time in the following game against Newcastle, Fletcher was the first player Amorim looked to. "The best six days of my life," he said afterwards.
The 18-year-old made his third appearance in a row when he again came on at the break against Wolves a few days later, though he failed to make an impact in the hugely disappointing 1-1 draw which spelled the beginning of the end for Amorim.
Curiously, he did not play against Burnley or Brighton when his father was in charge, with the interim coach keen to avoid accusations of favouritism towards his sons while Kobbie Mainoo and Bruno Fernandes returned from injury at the same time.