Ledley and Adam Matthews could directly face Parkhead team-mates Scott Brown and James Forrest as both countries look for their first win in Group A. The former Cardiff midfielder is anticipating a tough night against in-form Celtic skipper Brown.
"There will be a lot of battles in the game," said Ledley, speaking alongside Forrest at Hampden in a promotional press conference for Vauxhall, official sponsors of Home Nations International Football.
"James up against Adam and me up against Scott Brown so there will be key battles and we will see who comes out on top.
"We play against each other in training every day and we know each other's strengths and weaknesses so it is going to be a good game and we look forward to it.
"Scott is fantastic. He is one of our better players this season.
"He drives the players on and tries to attack as well.
"I am going to be on my toes and it is going to be a difficult evening for me."
Brown is back in Craig Levein's plans despite battling an on-going hip problem while Steven Fletcher and Darren Fletcher have also returned to the fold. The Sunderland striker has ended his self-imposed international exile, which began in February 2011 when he informed the Scotland camp by text message that he did not wish to be considered for selection. His Manchester United namesake is back in contention after a lengthy lay-off forced by a chronic bowel complaint. Forrest said:
"Looking at the squad and seeing Steven Fletcher, Darren Fletcher and Scott Brown back, they are three big players and it is a boost for us in the next two games.
"Steven is scoring week in, week out in the Premiership and we want to play with the best players.
"He is definitely up there so we are delighted he is back in the squad."
Ledley admits Fletcher will be the one to watch. He said:
"He is a fantastic player and scores goals and he is going to be a big threat to us, so we will need to be on our toes."
Wales lost their opening two qualifiers to Belgium and Serbia while the Scots drew against Serbia and Macedonia at Hampden. The defeated side at the Cardiff City Stadium will surely kiss goodbye to hopes of reaching Brazil although Forrest refuses to be pessimistic.
"That would be only the third game so you can't rule anybody out," he said.
"There is still a lot of football to be played but a win would definitely give that team the upper hand."
Ledley, still smarting from a 6-1 defeat in Serbia last month, admits the chances of qualifying for either country are already slim. The former Cardiff player said:
"It is going to be difficult.
"If you look at Belgium's team, they have got some fantastic players and the same with Croatia.
"So it is a hard group but we have to take it game by game and see how many points we end up with.
"But realistically, it is going to be very hard."
Meanwhile, Huddersfield centre-back Joel Lynch has withdrawn from the Wales squad for the double header against Scotland and Croatia as he has a small piece of bone floating in his knee.
"Joel will wear a brace for the next four or five days to help the healing process,"
Huddersfield manager Simon Grayson told the club's official website.
"He'll return to see the specialist at the end of this week and hopefully will be given the all clear."
Swansea confirmed their 21-year-old defender Jazz Richards, who has one cap, had been added to Chris Coleman's squad.