Aaron Hickey, Scott McKenna and Lewis Ferguson missed group training ahead of Scotland's final World Cup Group C fixture against Brazil on Wednesday.
However, it is understood all three were doing individual work at the Scots' base in Charlotte, North Carolina.
Right-back Hickey came off in the 1-0 win over Haiti and was absent for the 1-0 defeat by Morocco on Friday at the Boston stadium.
Centre-back McKenna has been managing a calf complaint and has yet to feature while Ferguson played the whole 90 minutes against Morocco.
Kieran Tierney was taken off against Morocco in the second half with cramp but he trained with the rest of the squad on Sunday morning.
Scotland are guaranteed to finish in third place and three points could be enough to get them through to the knockout stages for the first time.
A point against Brazil in Miami would all but guarantee that historic feat, a first ever win against the South American side would guarantee it.
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Meanwhile, assistant head coach Steven Naismith has said there has been a leniency in refereeing at the 2026 World Cup.
The Scots had two penalty claims turned down in the Morocco defeat when John McGinn and Scott McTominay went down in the box.
Former Scotland striker Naismith also noted that France star Kylian Mbappé had a penalty claim ignored when he went down in the box following a challenge from Senegal's Sadio Mané. That incident was reviewed by VAR but referee Alireza Faghani stuck with his original decision.
Asked if he has noticed a difference in refereeing, he said: "Yeah, definitely. I think if you look at a lot of the contacts that are made, they are less likely to be given.
"And that's the ones where a player is maybe just gliding past and it doesn't take much for them to go down.
"I think for the last four or five years, that would have been given as a foul definitely in this tournament, it's not and there's a lot of the transition moments happening because of it.
"One that comes to mind the other night is Ryan Christie in the first half, where if they go and score maybe it gets looked at.
"But we definitely feel as though they are being refereed differently.
"Mbappe's one in the box, John's one in the box, Scott's one in the box, it's not what I think everyone expected."
Scotland have faced Brazil four times in the group stages of the World Cup, drawing 0-0 in 1974 and losing 4-1 in 1982, 1-0 in 1990 and 2-1 in 1998.
Information from PA contributed to this report.