This may happen if you import your league into the Draft Wizard via sync before your league's keepers have been successfully identified. There are two ways to rectify this, but please make sure you delete your Draft Assistants before exercising these options, otherwise they may not work:
1. You can manually edit your keepers (click My Leagues > click Edit under Keepers). Then, do not re-sync your league's data with the Draft Wizard after doing so.
2. You can re-sync your league data with Draft Wizard once your keepers have been finalized in your league. To do this, click My Leagues > click Edit under Keepers > click on the Sync Keepers button in the top right of the screen. This may not work if you're in a Yahoo! league since Yahoo! only sends keeper data 30 minutes before the start of your draft.