The 26-year-old Celtic star will win his 50th cap if he plays in the game in his hometown at the Cardiff City Stadium, where he made his Wales debut against Poland in 2005.
Ledley who began his career with Cardiff City before joining the Hoops in 2010, said: "I am absolutely delighted and buzzing for Saturday.
"It's a great honour for me and my family so I am looking forward to it and hopefully getting on the pitch for it.
"It's special for it to be at Cardiff City Stadium, where I came through the ranks and learnt all my football.
"When I was a kid I just wanted to play football and go out there and show the world I could do it.
"A lot of people do not make it to play for their country and it's a fantastic honour, and I try to do it as well as I can."
Meanwhile, Liverpool goalkeeper Danny Ward has joined Ledley in the Wales squad after Lewis Price of Crystal Palace was forced to withdraw with a back injury.
Price had only been called up on Wednesday after West Brom keeper Boaz Myhill pulled out to have treatment on an Achilles problem and ligament damage to his left thumb.
Watch Wales take on Finland live on Sky Sports 2 HD from 5.45pm on Saturday.