Scotland boss Steve Clarke is remaining optimistic on the injury front ahead of the Euro 2020 play-off semi-final against Israel at Hampden Park on March 26.
Clarke said: "I am keeping my fingers crossed that the three mentioned recover well and can be available in March.
"It will be close for all of them but always hopeful, never ruling anyone out at this stage.
"There is still a long time to go before we get to March.
"I've had feedback from the medical departments, all three are working towards recovery. Whether they make it or not is a different story.
"I am optimistic that they will all make it. That's what you have to be.
"I think they will be close. Whether they are close and make it or close and just miss it is going to be decided by recovery.
"Without having first-hand knowledge of how the clubs recover the players and having the exact details of how the recovery is going to be, then it is difficult for me to gauge it.
"I do know that all the players will be doing their best to be fit and I am sure the clubs want them fit to help their own cause anyway, it's just wait and see what happens."
Tierney has had surgery on his dislocated right shoulder but is not likely to return to full training until March.
McTominay is recovering from a knee ligament injury picked up on Boxing Day, while McGinn fractured his ankle in December and is set to miss up to three months.
Clarke said: "If we got one of them back you could lose someone else, so there is lots that can happen over the coming days and weeks.
"Lots of games to play, I am sure there will be some good news and bad news and hopefully more good news than bad."
Clarke is confident he has plenty of cover available.
The former Kilmarnock boss said: "Stuart Armstrong has played his way in (to the Southampton team), Kenny McLean is doing well at Norwich.
"John Fleck has been really good at Sheffield United this season. I enjoy watching them. I have John Fleck and Oli McBurnie there, they are a good team to watch, they play well.
"A lot of time the media like to talk about players not in the team. I thought the midfield pairing I have had in the last couple of games, Ryan Jack and Callum McGregor, did very well for us.
"Kieran hasn't been in any of the squads I have had so far. If he was to make this squad it would be great, if he doesn't then I have left-backs who have been in the squads and done well for me.
"Greg Taylor has come in for the last couple of games and did excellent for us, having not played a lot of minutes with Celtic. It is always good to remember the ones who have done well for you."