Okay, I figured it out. He was there in the "ALL" column, but not on any of my rosters. After deleting 26 players from my AAA club (I like to trade for prospects...

), he reappeared. Of course, I had to delete 18 more in order to make sure that it wouldn't happen again. I finally got it to the point where there were 39 players on my AAA roster, and "Automanage minors" didn't push it back to 40 without changing my AA and A roster numbers. So OOTP5 doesn't check to see whether the ceiling number of players has been reached at a particular level before promoting them? Should definitely be a priority for future releases. Not that Markus has a lot on his plate or anything...
So, it looks like Mr. Big Boy won't be getting his ransom money after all!