No. During the Republic that consuls acted as commanders-in-chief, but this was an "on the spot" position--if they were physically present at the army they were automatically in charge, but given the difficulties of communication actually micromanaging from a distance was practically impossible. If more soldiers needed to be committed to a particular theater, it would usually be the job of the consul to raise the troops, or a departing consul who is taking up the post of governor in the province. However, the Senate could also raise troops and send them over without a change in command.

The Principate operated in much the same way, except that the emperor operated on top of the system.