Cardiff will make a late decision on the fitness of talisman Craig Bellamy.
Bellamy, one of three players manager Dave Jones is waiting on, was forced off after just 17 minutes of Friday's goalless first leg nursing a hamstring strain.
Jones said: "We'll leave it as late as possible, he's still got a chance and we'll look at him on Tuesday. He came off as quickly as he could get off so we'll just wait and see."
As always, Jones is remaining coy regarding the identity of his two other injury concerns.
Goalkeeper Tom Heaton went into the Madejski Stadium clash carrying a groin strain, but was named among the substitutes and could well be one of those still struggling, with Paul Quinn possibly the other after he came off in the 85th minute to be replaced by Lee Naylor.
Jones made two changes for the first leg from the final day draw at Burnley, with midfield pair Mark Hudson and Jason Koumas relegated to the bench in favour of Darcy Blake and Jay Emmanuel-Thomas.
Reading have added Jimmy Kebe to their squad for the trip to the Welsh capital.
The Malian winger has missed the last five games with a thigh strain, but has a chance of featuring and will travel as the Royals look to book a place at Wembley.
The sides fought out a tense 0-0 draw in Friday night's first leg and manager Brian McDermott - who played for Cardiff - will also hand a late fitness test to Hal Robson-Kanu.
Robson-Kanu has stood in for Kebe in recent weeks, but sustained a hamstring problem last Friday night and will be assessed on the day of the game.
Midfielder Mikele Leigertwood shook off an ankle knock to play in the first leg and Noel Hunt will again partner Shane Long in attack.
Long has scored 21 Championship goals this season, but has not netted in his last five appearances.