Low strategic rating could be the problem. Every commmander has a strategic rating (1st number of the 3 for the commander). The values range from 1-6 (a 0 is possible, but I don't remember seeing it, and technically I suppose so is a 7 or 8). With a 3 strategic rating, a commander should be active about 50% of the time. With a 4 value, he will have a better chance of being active. A general must be active to conduct offensive operations.
The values are not set in stone, and a commander's stats can change based on experience gained, or commander bonus/maulus, or other factors.
Also, some commanders have abilities that hurt their chances to be active (for example, I think it's called "cautious strategist", with which the general will be inactive if a "die roll" is under the friendly military control value).
Remember - The beatings will continue until morale improves.