is it really tho?? i mean madara can teleport any part of his body that he wants!!! now let that sink in for just a second.....now does it seem absurd to have both sage mode and flying thunder god?!?! not really, and someone said earlier that maybe minato only knew the frogs because he summoned gamabunta, because naruto summoned gamabunta and didnt have sage mode, here is my response
1. yes naruto summoned gama wit out sage mode, but he also didnt know fukasaku when he did that, naruto met fuka specifically bcause jman wanted naruto trained in the sage arts, had naruto not been trained in the sage arts he would not have known fuka.
2. sage mode is only for those with large amounts of chakra, a very large amount of chakra is needed to summon gama, minato could summon gama, meaning he had a large enough chakra reserve to both summon gama, fight the kyuubi and gaara, and seal the kyuubi within naruto all in one night. i dont know about you guys but that sounds like minato had an enormous chakra reserve. i mean the 3rd could barely seal the 1st, 2nd, and oro's arms, after summoning the monkey king, which i doubt took as much chakra as a gama summoning.
im not saying he was definately a sage, but with the info we have been given, it points to minato at least having the potential to undergo sage training.