Wigan will be big underdogs when they take on Manchester City in the club's first FA Cup final, and they have not been helped by a string of untimely injuries.
The Latics looked to have overcome an injury crisis that contributed to a poor run in the Barclays Premier League earlier this season but the problem has returned.
Antolin Alcaraz, Jean Beausejour (both hamstring), Maynor Figueroa (groin) and Ronnie Stam (ankle) have all picked up knocks in recent games, joining long-term absentees Albert Crusat and Ivan Ramis on the sidelines.
Alcaraz is the only one of the six who has a chance of playing again this season, but the cup final may come too soon for the influential Paraguayan.
Caldwell said: "It's one of the worst things in football to be injured and to miss any game but to miss a game as big as this is a big blow for them and hopefully the team that goes out can put in a performance that wins the game for those guys.
"Throughout the course of the competition it's been a real squad effort, from the younger players who started the competition to get us through the early rounds to now the team that's been playing in the last couple of rounds."