Patterson, Steve Clarke confirmed, is a doubt for the crucial World Cup play-off at Hampden Park on Wednesday.
With Kieran Tierney out, the Scotland boss could be forced into two changes in his backline.
Scott McKenna or Liam Cooper will fill the huge Tierney void as left-sided centre-back.
Options on the right include Ralston, Aaron Hickey and Stephen O’Donnell.
Former Scotland boss Craig Levein believes it should be the Celtic right-back but wouldn’t be surprised if Clarke opted for O’Donnell.
"He might go with O’Donnell”, he said on BBC Sportsound. “He does, at times, tend to go back to the guys who have done well for him.
"I’m his [Hickey’s] biggest fan but I just look at this game and think he might just need a wee bit experience. He might go with the experience. If Patterson was 100 per cent I’d have put Patterson in but I think he’ll go for O’Donnell over Ralston.
"I would pick Ralston. He’s on the way up and he’s one of those players who has been improving. All credit to Celtic and Ange Postecoglou for the transformation almost of what looked to be an ordinary, without trying to be disrespectful at all, player into an international player.
“Lots of managers had been at Celtic before Ange hadn’t recognised the talent Ralston has or maybe it wasn’t there at the time.
“It just shows you what one really good manager can do to a player.”