Although Rangers have conceded 28 goals this season - only five Championship clubs have leaked more – keeper Smithies has been the standout player.
Hall believes the goals-against column would make grimmer reading without the former Huddersfield custodian, and therefore he could creep on to the radar of new England boss Southgate.
There is a recent precedent for second-tier keepers getting a call-up: Burnley’s Tom Heaton was picked by boss Roy Hodgson in May 2015 despite the Clarets' relegation to the Championship.
“I believe playing for England is a possibility for Alex,” said Hall.
“He has been our best player this season and was fantastic last season as well when he came into the side.
“He has saved us on so many occasions this season and he is still a young keeper too.
Smithies earned England youth caps at every level from U16 to U19, including five appearances at the FIFA U17 World Cup in South Korea, 2007.
And like many of the modern breed of custodians it’s not just his hands which do the talking for him.
According to Hall, he has wider skills currently helping Rangers make the transition to a more aggressive, possession-based style of play by playing out from the back.
“His shot stopping is unbelievable at times, but he can play as well,” added Hall. “He is very good with his feet. He works hard in training, but he is just a very talented keeper, very gifted – I’ve got high hopes for him.”
Who is the most vulnerable in losing his England place to Alex Smithies?
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