Jacob, 17, joins fellow Aussie goalkeepers Alex Cisak and Dean Bouzanis at the third tier club.

The Sydney-born youngster, who joined the Red Devils in July 2010, is seen by Oldham boss Paul Dickov as a long-term prospect after previously impressing on trial.

"Liam is not ready for the first team and we have signed him for the longer term,” Dickov told the club's website. "He comes highly recommended by Eric Steele (United's goalkeeping coach) and probably would have got another deal but for the keepers ahead of him at Old Trafford.

"Liam impressed us with both his ability and attitude last season and we are looking two, three, maybe four years down the line."

Dickov explained that United had allowed Jacob to leave, in order to not get in the way of his senior career.

"The main reason United agreed to let Liam go was because they didn't want to hold back his career,” Dickov said. "They have David de Gea, Anders Lindegaard, Ben Amos, Sam Johnstone and Eire under-17 keeper Joe Coll so his opportunities would have been limited at Old Trafford."

Oldham goalkeeping coach Paul Gerrard added: “I am over the moon we have signed him because if if he works hard and keeps his head down he has a bright future in the game. Liam is 6ft 3in, a great shot stopper and his agility is second to none."