The 24-year-old is making his sixth temporary move away from the Reds after joining the club's Academy in 2015.
He has made three competitive appearances for United's senior team, the last coming against Burton Albion in the EFL Cup in September 2017.
The Portugal Under-21 international has previously gained experience at Rochdale, Belenenses, Vitoria Setubal, Kortrijk and, most recently, Hearts in Scotland.
He played 20 times in the Scottish top flight and made a further five appearances in cup competitions for the Edinburgh outfit.
United have, this week, rewarded Dean Henderson a new contract with the goalkeeping department at the club looking incredibly strong.