Promotion-chasing Derby suffered back-to-back league defeats for the first time this season as second half goals from Dale Stephens and Kazenga LuaLua gave Brighton a 2-0 victory.
Sir Alex Ferguson has hailed the decorated career of Dave Mackay as tributes continued for the former Tottenham, Derby, Hearts and Scotland midfielder.
Brighton defender Bruno could miss the visit of leaders Derby.
Former Tottenham and Hearts captain Dave Mackay has died after a long illness. He was 80.
Derby teenager Offrande Zanzala has signed a professional contract with the club.
Derby defender Shaun Barker is set to continue his return from injury with a run out for the Sheffield United development side.
Fulham boosted their Championship survival bid and dented Derby's automatic promotion hopes with a shock 2-0 win at Craven Cottage on Saturday.
Steve McClaren admitted Derby missed an opportunity to take a big step towards the Premier League after a "bad day at the office" in their defeat to Fulham.