Thomas was expected to have an operation yesterday to put a plate and screws in his thumb. Owen is odds-on favourite to take over after deputising for Thomas in the second half against France when Wales turned a 15-6 deficit into a 24-18 victory.
"The selectors will sit down and talk about it but I would have thought Michael Owen would be our captain," said Ruddock. "He did a superb job in the second half against France."
The Newport Gwent Dragons star said: "You dream about playing for Wales, but it never enters you head that you will one day captain your country. If it comes about it will be brilliant, but we will just have to wait and see.
"It's an easy job really because there are so many experienced players in the side. But it will be a massive honour. Gareth is going to be a massive loss because he is a brilliant player and he has done a fantastic job since he has been captain.
"He has put his own unique stamp on things. We are going to miss him but the strength of the squad is shown when you have someone like Kevin Morgan to step in. He has been playing fantastically well and is just as good as Gareth."
Though Wales are joint top of the championship table after being unbeaten in their first three games, Owen is refusing to take the Scotland clash lightly.
"Scotland are improving all the time. Like us they did well in France and were unlucky not to get a win. And against Ireland they played fantastically well in the first 15 minutes before falling away. They are probably going on a similar journey to the one we have been on in the last couple of years. It's going to be a massive challenge for us. They know the way we play and it's going to be tough."