So it would appear that Bo Jackson has been combined into one entry despite being a multi-sport athlete. Hence the reason you are seeing those cards listed under football. I would assume that since you have no football cards, it is showing you the team names for the cards you do have. It makes since to have one single entry for the dual sport Bo Jackson, but at the same time, I would argue that keeping them separate has its benefits as well. However, he isn't the only entry on the database that has a dual sport background. Now granted, it is guys like Wahoo McDaniel (football, Wrestling), Brock Lesner (MMA, Wrestling), Dennis Rodman (NBA, Wrestling) and Deion Sanders (football, baseball). However, I always try to use the PID already established for their primary sport. I would guess that is the case for Mr. Jackson here. It would however, make sense that since you don't have any of his football cards collected that you shouldn't see an entry for cards there. Maybe that should be brought up to Admin's attention on the "To Do" forum.
What?? No American Ninja Warrior cards or Ninja Warrior cards yet?? Someone is really slacking!!