The 25-year-old, who joined Preston from Peterborough over the summer, suffered a foot injury in training earlier this week.
"He is the only doubt at the moment," said Toshack.
"I think he'll be OK. He went for an X-ray yesterday morning and it didn't show anything important.
"Hopefully he will be able to train today. He was able to do some running yesterday - no contact with the ball at all - but hopefully he will come through OK."
Wales have not featured in the finals of a major tournament since 1958 but Toshack has brought through a host of new youngsters who have given fresh hope to the nation.
Toshack admitted there are nerves in the camp.
He said: "I think they are a little bit tense. At the same time they want to do well, they realise the importance of getting off to a good start.
"When you look at the teams in the group, it is a very open group.
"England would be the favourites but there is not a great deal to choose between the rest of us."