The Greek has missed his side’s previous two games with illness – the goalless draw with Hibs at Easter Road and the 2-0 win over St Mirren in midweek.
The 27-year-old has scored seven goals since his £3million move from Dutch side VVV Venlo in the summer including a hat-trick on his last outing against Dundee.
His return is a boost for manager Ange Postecoglou, who has also had to make do without top scorer Kyogo Furuhashi since Boxing Day.
Postecoglou said: "He [Giakoumakis] is fine. I made a decision on Wednesday that it was best not to push him, we had some options.
"He trained on Thursday with the guys who weren't playing and then trained fully today.
"No-one came out with anything from the game so it's the same sort of squad plus Giorgos."