Centre-half Nelson, 32, signed an 18-month contract at Valley Parade last week after Bradford agreed an undisclosed fee, believed to be in the region of £30,000, with Scottish Premier League side Kilmarnock.
Parkinson has no new injury or suspension problems following last week's Johnstone's Paint Trophy defeat at Crewe, while several players will have had chance to rest various bumps and bruises following the postponement of Saturday's league game at Port Vale.
Goalkeeper Matt Duke, defender Rory McArdle and skipper Gary Jones are expected to return to the starting line-up, while winger Kyel Reid and on-loan Newcastle defender Curtis Good are hoping to keep their places in the side.
Another defender, Stephen Darby (foot), striker James Hanson (toe) and winger Will Atkinson (stomach) were all due to face late fitness tests ahead of Saturday's game and could also return to contention as the Bantams bid to defend a 3-1 first-leg lead.
- Sports & Recreation