Though it does not happen often, the armed services can recall to active duty a member of the US military for a variety of reasons.

I personally know of a case involving a lt. general whose recall stemmed from the fact that the higher brass (of which there aren't many!) wanted to investigate his handling of some military matters at a hospital under his jurisdiction. It happens a bit more frequently at lower grades, generally to get someone into the military justice system.

But in time of war your general could be recalled for reasons more salubrious to his health, in which case he might very well get that promotion!

TdE


TEd