The Wales international got his first taste of action this summer when he played for around half-an-hour in the friendly against Borussia Monchengladbach on Saturday.
Ledley is not expecting to start Wednesday's match, but he is keen to be involved as the Hoops gear up for another big European night.
"My fitness is getting there. I played 30 minutes on Saturday, which was a big bonus for me," Ledley said.
"I'm obviously still not match fit because I've only played 30 minutes so far but hopefully I will be in the squad for Wednesday.
"It would be brilliant if I could get involved. I'm going to be a little bit rusty as I haven't played much, but if I am starting I'll give it my all."
Meanwhile, the 26-year-old has played down continued speculation linking him with a return to Cardiff.
Ledley added: "It's just rumours at the moment. There has been nothing official.
"A lot of players want to play in the Premier League and that's why they have done pretty well with their signings so far.
"It does attract people but, at the moment, I'm with Celtic and I'm just concentrating on a big week ahead of me."