Ange Postecoglou admits his Celtic squad needs "significant change".
The 55-year-old, who replaced Neil Lennon as manager last month, knows he has his work cut in order to catch Rangers.
"I think there will be significant change, only because there has been a pretty big turnover in players from last year," Postecoglou told Sky Sports News.
"A lot [of players] have left and we need to bring in some, and whenever that happens I think that is significant change.
"Also we will probably play a little bit differently to what they have played in the past, so whether it is a rebuild or just a shift in direction it will be significant change for sure
"I'm not talking to anyone, we have got multiple targets and there's a lot of names being thrown around.
"From my perspective, it's more about making sure that we do bring in some players who can play the football that I want over the next period and the club are working awfully hard to make that happen."
