O'Donker, 17, joins on loan from Sky Bet League One side Oxford United for an initial one-month loan.
The teenager became the U's youngest ever player back in December 2020 (aged 16 and 55 days), when he came on as a substitute in United's Papa John's Trophy tie with Forest Green Rovers, scoring the first penalty in a 4-1 shootout win.
We'd like to take this opportunity to welcome Gatlin to the club and thank Oxford United for their cooperation in this loan agreement.
#WelcomeODonker