The "Fred thread": the Argead Macedonian Army

[Paralus]

The statement that Antigonus "had taken over the army that had been with Eumenes" is a broad general one - and as you noted, even Diodorus has around 2,500 men of this army stay with Eumenes, again the numbers tying in.....

Aside from the current notice of troops being taken over or transferring allegience (Eumenes' army of Orcynii), there are others in Diodorus I did not have to hand: 18 75.1; 19 11.2-3; 43.8; 50.1; 50.3. We can add to this Diodorus' insistence that Antigonus did, indeed, take over Eumenes' army when he reports Antigonus' intentions after the death of Antipater (18.50.1 & 3 ):

In Asia, as soon as the death of Antipater was noised abroad, there was a first stirring of revolution, since each of those in power undertook to work for his own ends. Antigonus, who was foremost of these, had already won a victory over Eumenes in Cappadocia and had taken over his army, and he had also completely defeated Alcetas and Attalus in Pisidia and had annexed their troops [...] For at that time he had sixty thousand foot-soldiers, ten thousand horsemen, and thirty elephants; and in addition to these he expected to make ready other forces also if there should be need, since Asia could provide pay without end for the mercenaries he might muster.

And one might not doubt those figures given that Eumenes is still locked away and the demise of Alcetas and Attalus. Antigonus seems well practised at "taking over" opposing armies...