Not sure it was that as such but Carrick himself mentioned on occasion that they wouldn't risk players if they didn't need to so we probably had players who could have played (and almost certainly would have done in the old days) but didn't.
I think this is exactly the situation, no doubt he will be considering whatever other options are available. Of course, we may not leave any offer on the table indefinitely either.
Unless you are a regular in the dressing room how can you know this? All we can see as fans is he has made captain by repeated managers so I'm guessing they see some leadership qualities.