First, I am not using some magical "inside information". I have no solid information about any future resignations or appointments until they are announced in Rome. However, I have been studying the comings and goings of bishops - especially in the USA - for over 10 years (mostly relating to my Catholic-Hierarchy project).
There are a lot of common factors - some canonical - others practical - that go into selecting candidates for a diocese.
It should also be noted that Pope Benedict XVI has been reigning for less than 3 years. He may, over time, develop substantially different patterns than his predecessor. Only time will tell.
I should also note that I in no way am suggesting that any bishop is seeking to move to another position when I indicate I think it might happen. Few if any Bishops desire to leave their current flock - but if the Pope asks them to take a different role - they must seriously consider it.
So let me summarize how I do the analysis (and in no particular order).
- Vacant sees are the highest priority (i.e., they often get attention before replacing a healthy ordinary that is past 75)
- The normal retirement age for a bishop is 75. Upon that age he is asked to submit his retirement, which can be accepted (or not) by the Holy Father at his leisure.
- Cardinals are often kept as ordinaries past 75 - but rarely past 80.
- Bishops that are asked to take a new post are often sent back to the region, if not the diocese, that they started out in.
- Coadjutors typically serve 6 to 18 months before the previous ordinary retires.
- Vacant dioceses typically take 6 to 18 months to fill.
- Once over the age of 67 or so, few bishops are considered for new posts.
- Auxiliary Bishops, if they are considered for other roles, typically have 6 to 8 years of experience as an Auxiliary. But those that have 10 to 12 years of experience or more are rarely considered.
- Auxiliary Bishops that were priests in the same diocese are less likely to be considered (except as the ordinary of that diocese).
- Priests that are considered for a post often have some connection to Rome. (Perhaps studied there as a seminarian, got an advanced degree there, or worked in some small way in the Roman Curia.)
- Also priests that have some seminary background (Rector or other administrative experience, or as a professor) are more likely to be candidates.
The most important thing to note about the above - they are _only_ talking about generalities and patterns. I can cite modern examples which contradict every single one of them.
Ok, that's enough for now. I hope that makes some sense and helps to explain the various overviews I have written and the ones I will be writing.