Record signing Lukaku missed Tuesday’s Champions League quarter-final second leg against Real Madrid due to an Achilles issue but has now rejoined group work at Cobham and is set to be fit to play at Wembley.
His return is a boost for Chelsea, who will be looking to keep their season alive after their agonising European elimination.
Callum Hudson-Odoi remains sidelined with his Achilles injury and Ben Chilwell (knee) is a long-term absentee, but other than that Thomas Tuchel has a fully-fit squad to choose from.
After playing 120 minutes at the Bernabeu in midweek, Tuchel may look to freshen things up against Palace.
Captain Cesar Azpilicueta is likely to come into the back three, with Reece James switching over to right wing-back.
Apart from in the quarter-final against Middlesbrough, Kepa Arrizabalaga has been Chelsea’s FA Cup goalkeeper this season and Tuchel faces a decision over whether to start him or Edouard Mendy against Palace.
Mendy was preferred for the Carabao Cup Final against Liverpool and Tuchel could stick with his No1 given the importance of the game.
“Romelu was back in training on Thursday,” said Tuchel on Friday. “Let’s see if he can get any reaction or not.
“Except for Ben Chilwell and Calum Hudson-Odoi everybody seems to be OK. Fingers crossed it will stay like that.”
Predicted Chelsea XI (3-4-3): Mendy; Azpilicueta, Silva, Rudiger; James, Jorginho, Kante, Alonso; Mount, Werner; Havertz.