The 20-year-old has joined League One Fleetwood Town managed by Grayson, for next season.
It will be the third loan spell of the York City product's career. Last season was split between Aberdeen and League One Northampton Town. He scored two goals in each spell, which totalled 16 starts and 21 substitute appearances in all competitions.
Edmondson made his Championship debut as a 16-year-old substitute at home to Queens Park Rangers in May 2018. His only subsequent first-team appearance came from the bench against Birmingham City that September.
Quick and agressive, Edmondson will have one further year on his contract when his time at Highbury comes to an end.
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