It is possible.
How the f*ck do I fail? It makes perfect sense if Dan is his father. Remember, Dan died a LONG time ago, I don't want to hear "Oh Dan is too young to be Minato's dad."
THEY LOOK JUST A F*CKING LIKE! Plus if you think about it, it could make perfect sense. Dan could be Namikaze, Tsunade IS senju, Minato could be their son, Plus, look at Naruto for a second, he looks JUST like Hashirama, only with whiskers and blonde hair, even Tobi says he sees the first hokage in Naruto, but that's besides the point.
Dan loved Tsunade, Before he died, he may have conceived a child with her, and since Minato grew up without his father, Tsunade was so sadden and heartbroken, she left the village, THUS when she says in this LATEST chapter, "After you died, I escaped from your memory". You guys have to think outside the box.