These are players that are usually retiring, but does mean that they definitely will be retiring at the end of the season, or is it just pot luck if you sign one and hope they won't retire?
If I remember what I have done my first season, you can't sell nor fire players who will be retiring at the current season, which means those who are on the transfer list, are retiring at least, next season, as they could not have been sold or fired by players.