Kyle Edmund, 20, is favourite to be thrown in at the deep end and handed a debut in a competition that Britain has not won since 1936. But he is currently still playing a Challenger event in Uruguay.
The more experienced James Ward, who thrillingly beat world number 11 John Isner in San Diego in the first round, is the other option and, like Edmund, is also in form, having won a Challenger on clay last week.
Edmund won a claycourt Challenger in Argentina last week and another strong run in Montevideo this week could see him rise higher than his 99th ranking and earn a main draw entry into next year's Australian Open.
However, that could mean he does not arrive back in Europe until Monday, four days before the Davis Cup final.
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"It's an issue but he was hell-bent on going there which is good for him," Smith told the BBC. "He has his career to think about as well, and to be honest I'm happy if the players come in a bit fatigued by winning matches.
"I'm ok with that rather than three or four weeks of practice, which is not the same."
Smith said he would decide whether to play Edmund or 155th-ranked Ward in the next few days.
"I'm going to need a few more days to rally my head around it and come to a decision based on who I think can win the particular match," he said.
But he will have no qualms about throwing Edmund into battle. "He qualified for the French Open and beat home player Stephane Robert with the whole crowd against him," he said.
Smith's options were made clearer this week when world number 45 Aljaz Bedene, who now has a British passport after representing his native Slovenia in the Davis Cup, had his appeal against an ITF rule declaring him ineligible for selection for a second nation, postponed until March.
(Reporting by Martyn Herman,; Editing by Neville Dalton)
