As I mentioned earlier, it didn't seem likely that the Detroit Lions were going to go into the regular season with only three true running backs and 10 offensive linemen. As it turns out, that's because they aren't planning on going into the season with 10 linemen.
Dave Birkett reports that offensive lineman Chris Morris was released today, opening up another spot on the roster. It's likely that the Lions claimed to take Morris' spot on the roster, whereas Aaron Brown was released so the Lions could add someone else.
It's not clear who the second new player to be added to the roster is right now. I'm assuming it's a running back, though. If McClendon was added to take Morris' spot, you have to imagine the Lions released Brown in favor of a running back. That would make the most sense and would explain why he was released.