Unless the captain isn't the main character. You could have a show where the lead characters belong to the team that goes on missions and their commanding officer is a supporting character, as with Stargate SG-1.
Not to hijack this, but why hasn't an idea like that been explored for Star Trek
? It's not the traditional Trek
format, but it might make for an interesting series. I am, of course, speaking only about TV series and not books or e-novels, as I know that some of these focus on characters who aren't captains or have a commanding role.