Fraser Forster will stay at Celtic for the rest of the season as Southampton did not insert a recall clause in his loan to the Scottish champions.
Forster helped win the League Cup at the weekend and has impressed during his return to the Parkhead, while Angus Gunn and Alex McCarthy have shared duties at St Mary’s.
But Forster, 31, cannot be called back mid-season to compete for his place in Ralph Hasenhüttl’s team, according to a Celtic source.
Hasenhüttl dropped Gunn after conceding nine goals in the defeat to Leicester in October, while McCarthy has failed to stop his team conceding goals in their battle against Premier League relegation.
Forster is the club’s in-form goalkeeper at the moment with his displays in Scotland over the last three months.
He returned to the club where he spent three years before moving to the south coast in a £10 million move.
Forster was picked for England while at St Mary’s but lost his place last season and was allowed on loan this summer.
Former Celtic centre-back believes his performances are worthy of a recall to the national team.
"He just needs to keep doing what he's been doing, performing very well, and if he does then I'll be very surprised if a call-up is not coming for him very shortly," Stubbs told the BBC.