The champions head into the new campaign without prolific forward Gary Hooper after he sealed a move to Norwich.
Ledley has every faith in Anthony Stokes' ability to help plug the gap and weigh in with some goals, but believes the Hoops need even more firepower.
The midfielder said: "I think [we need] another striker.
"No disrespect to any that we've got but, with losing Gary, you've got to think of injuries as well.
"Another striker would be nice but that's down to the gaffer and the coaching staff to bring someone in.
"We all believe in Anthony Stokes. He's a fantastic player and since he's been here he has scored a lot of goals.
"Hopefully, we can get a nice partnership with him and a new striker that we bring in."
Meanwhile, Ledley has played down speculation linking him with a return to Cardiff.
Reports suggest the Bluebirds could be set to make a £3million bid to bring the Wales international back to the club he quit for the Hoops in 2010.
Ledley admits the prospect of playing in the Premier League is a big attraction for some players, but insists his focus is on the Scottish champions.
He said: "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."
Ledley has been hampered by injury during pre-season but made his return to action in Saturday's friendly defeat to Borussia Monchengladbach and he now hopes to have some part to play in Wednesday's Champions League qualifier against Elfsborg at Celtic Park.