
The 20-year-old saw his last loan spell cruelly cut short in February - and returns until early January initially.
Gallagher, capable of playing at centre-back or in the centre of midfield, made five appearances in amber and black.
He has been allocated squad number 26 on his return and is registered and eligible to face Woking on Saturday afternoon.
The club would like to formally thank Lincoln City for their assistance to allow the loan move to proceed.