"I've not spoken to Walter about it yet but I'd imagine this will be my last qualification campaign."
The 31-year-old believes that the national team will ultimately benefit from his decision as younger players seek to establish themselves.
The former Celtic defender added: "There are a lot of young players coming through at the moment and it would probably be better if I got out of their way.
"I think that would be the best thing for the long-term future of the team.
"Of course I still want to play for Scotland but further down the line the team is more important."
Norway's late win over Slovenia on Saturday means Scotland need to beat the Scandinavians to stand any chance of claiming a very unlikely play-off place and possibly prolong the international career of McNamara.
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