Postecoglou was speaking after their 6-3 home defeat to Liverpool.
Asked about the market, the Australian said: "Yeah, absolutely. Some of them will be internal. We're at different stages of getting players back from injury. We've got a couple of long term ones in Vicario and Wilson, but the rest hopefully at some point in January they'll come back.
"That will help us in terms of just getting numbers back and dealing with the schedule, because the schedule is not going to change. We're in the Carabao Cup semi-final, we're still in Europe and the FA Cup starts. We're still in all the competitions, so it's not going to get any easier. We're going to need some of those players hopefully to come back and contribute.
Asked directly about buying, he added: Yeah, I guess if the right players are there. Again it's about making sure it's something that's going to help us continue to build on what we’re doing."