The former Everton striker signed for Leeds earlier this week.
Farke said on Friday: "We'll see. Each and every training session with the team is important for him. He had a long summer break, followed by a few weeks of individual training, where his general endurance was at a really good level. However, what he has missed is team training, and for that reason, each session is crucial.
"He has made a decent impression, already well integrated, and you can see from day to day that he is growing. When we will use him for the first time, we’ll decide spontaneously. From a fitness point of view, he’s in good shape."
On fellow attacking signing Noah Okafor, he added: "It’s at least possible because he was involved with AC Milan in the whole pre-season. He also featured last weekend for several minutes, so that means he doesn’t need three or four weeks to build up to match fitness. Let’s see how the next two days go, and we’ll make a late decision on him, but it’s at least possible."