There are only so many at bats to go around. So in essence, there IS an odd man out. Or potentially more than one. You don't have a young talent like Cowser and sit him on the bench indefinitely as a 4th OF.
Once Holliday (and the others) are up, that problem is only compounded. O'Hearn would be the odd man out, but I think we kind of know his days are numbered. Even if it's just 2024. He's a FA after this year (I think?) and there's no way we are extending him.