Some Generals fought alongside their soldiers. I did a quick google to confirm and as recent as WWII some generals fought while directing battle.
<PERSON> was known to join the fray when the issue was in doubt, inspiring his men and giving his loyal legions the desire to not only please him, but protect him.
The further back in history your battle is, the more likely that the leader will lead by example.
The battle scenes in War & Peace have a beautiful balance of this, giving the reader the prebattle prep and then going to the other officers. The general in that situation met with some controversy as part of his overarching strategy involved bringing the French in as deep into Russia as possible, ceding cities if he needed to. His strategy was brilliant and worked, oncoming winter was a weapon <PERSON> could not counter.
Have the commander, if popular enough, see that his presence is required at a particular point in battle and get on his horse and ride into the fray.
<PERSON>, in a desperate situation where he had led his men to attack from a disadvantageous position, took off his helmet and took a shield from a nearby legionary and ran into battle, fighting for his life as well as victory. 714
His men - outnumbered as was often the case - still prevailed as they needed to protect their beloved leader.
Such situations where the general must get his men to rally around him and strike through the enemy are extremely dramatic and dangerous. <PERSON> was often wounded in battle since he always fought with his men.
If fictional, choose the personality of your commander. Is he the sort whose presence with his men in battle would be enough of an advantage to counter the personal danger and tactical difficulty of the situation? Is he an Alexander who is always shoulder to shoulder with his men? Is he a Caesar who does this when the situation is grim? Had he been less popular, his appearance in battle would have merely reinforced what the men knew - we are losing this one. Rather, they rallied and fought for their general.
When commanders lead from a place within the battle, runners might not find them as easily, but signals still were in place so that reserves could be called in or sent to turn the enemy’s flank if the centre was doing well. 164