This is another example of sc-fi turning reality...
The Pentagon is putting aside $7 Million to create what is called the Avatar Project, which is just what you think... minus the tall blue aliens.
The Avatar Project will pair a soldier with a semi-autonomous bi-pedal machine to act as their surrogate. The machine counterpart, created by DARPA, will be controlled via special interfaces and algorithms (not yet developed).
According to the literature on the Avatar project, it seems the android counterparts would mainly be used for purposes like ensuring the safety of rooms or outdoor terrain, and recovering combat casulaties, rather than participating in the actual combat.