Shot-stopper Owen Mason joined the Celts on an initial one-month loan, soon extended until the end of January, from Mansfield Town in September.
The 18-year-old spent much of last season on loan in the Vanarama National League North at Guiseley, impressing in a side that struggled at the bottom of the division.
Mason has already represented the Republic of Ireland at Under 18s level, and was named in a 30-man squad for an Under 19s training camp earlier this summer.