United have since gone two games without a goal and Mourinho is keen to have Lukaku back to play a part - any part - at Wembley.
"Romero plays on Sunday because he deserves that, and some other players are going to play because we as a team achieve the second position and we, as a team, are going to play the FA Cup final", he said.
The burly forward suffered an ankle injury during United's 2-1 win over Arsenal on April 28 and has not been in action since then. 'Again we try to see if it is possible for the last match'.
Lukaku has scored 27 goals since joining United from Everton in a £75 million ($101 million) deal past year.
Hawaii Volcano Eruption and aftermath; dramatic visuals inside
Lava flows from the volcano, one of five on the island, have buried an area about 125 square kilometers, according to the USGS. Additional funds are needed to address the permanent damage the volcanic activity and earthquakes have caused, he added.
The Red Devils snatched a late victor against Arsenal through Marouane Fellaini, but failed to score against both Brighton and West Ham - although the midweek goalless draw to the Hammers did confirm United's second-placed finish in the table.
The Cup represents United's only chance of silverware this season.
"Carrick had already been decided".
Mourinho's expected to make up to eight changes to his side from the one that drew 0-0 with West Ham on Thursday. "The only problem was I also knew he didn't want to play me", Lukaku said.
"I knew I was going to play", he told Play Sports.
But the Portuguese hopes the Manchester United medical team can get him up to speed enough to have him on the bench.