The 35 year old Bermudan striker is out of favour at Reading's Madejski Stadium due to the Royals having to make a further payment of £50,000 to Manchester City if Goater were to play a 50th game for the Berkshire side.
The loan is City's last and if Micky Adams wants keeper Ian Bennett, he will have to find the money to sign him on a free transfer.
Adams told the club website:: "Shaun is an experienced centre-forward with a reputation for scoring goals. "I'm sure he will be a valuable addition to our side and hopefully he'll find the back of the net a few times along the way."