The 52-year-old explorer, named by Bild newspaper as Johann Westhauser, was seriously injured around 1,000 metres below ground by a rock fall in the Riesending caves near Berchtesgaden, Bavaria, on Sunday.
On Monday, emergency services managed to make contact with him, but police said the man was not able to be moved and a specialist rescue team was called in from Switzerland.
But on Tuesday a spokesman for Chiemgau Mountain Rescue said the explorer from Stuttgart was responsive and able to stand up for short periods of time.
Previously it was only thought he could be moved lying down.
The researcher, who was one of the first to discover the cave years ago, was exploring Germany's deepest and longest cave with two companions when he suffered injuries to his head and upper body in the rock fall at around 1.30am.
One of his companions managed to climb up the cave and raise the alarm, while the second stayed with the injured man. It took the climber almost 12 hours to get to the surface.
The rescue operation involves 200 people and the man could now be out by the end of the week. He will be brought in stages to five stations in the caves called bivouacs over the next three to five days, Chiemgau mountain rescue said.
Westhauser works at the physics department of the Karlsruhe Insititue of Technology (KIT) studying caves.