Celtic wait on scan results as key duo face battle to make Rangers clash
The Greek striker tweaked his hamstring and went off in the first half, while midfielder Turnbull – who has already missed a large chunk of the season due to injury – finished the game with a knock.
On Giakoumakis, Postecoglou said: "Nothing concrete yet. We are still waiting on the final scans from it. Hopefully it's not too bad. He feels like it's not too bad, but again, until we get the information, we won't know."
He continued to Celtic TV: "Similar with David Turnbull, he got a pretty hard knock. It's only been a couple of days so we will see how it all settles down with both of them. I'm hoping it's not too lengthy an absence."