Ok, new functionality.
You can release players from your roster using the "manage roster" screen found in the menu under your team name. That took about 2.5 hours to code, debug, and test, with just a couple of interruptions. Code was mostly borrowed from functionality elsewhere in the site.
We are not yet enforcing 53 man rosters, but will after the rookie draft. Still folks might want to cut the deadwood from their roster to better evaluate their needs.