The runaway Serie A leaders trail 2-1 from March's first leg, in which they lost for the first time at home this season, but may have a certain Italian World Cup winner back to aid their chances of overturning that deficit.
His signing would be made worthwhile simply if they can hold onto this advantage, and they may take a defensive approach as Juve need to score at least twice to progress.
Sitting back and hitting the opposition on the break worked perfectly for Vincenzo Montella's side as they did a job on Tottenham Hotspur in the Europa League earlier this term.
The pacey Salah is the perfect counter-attacking weapon, and the Egyptian winger has seven goals in eight games since arriving from Stamford Bridge in the January transfer window.
The latest of those came in Saturday's 2-0 win over Sampdoria, as he quickly added to Alessandro Diamanti's 61st-minute goal to secure the Florence outfit three points which took them fourth in the Serie A table.
Third-placed Lazio occupy the final Champions League qualifying spot and are five points ahead of Fiorentina. Overhauling them and reaching the final of the Coppa Italia would represent an excellent campaign for Montella's men.
Recent form (all competitions): LDWWDW
The Old Lady remain in the hunt for what would be a magnificent treble this season, having reached the Coppa Italia semi-finals and Champions League quarter-finals while maintaining their dominance in Serie A.
They only led the domestic standings by three points prior to the mid-season break, but a spate of Roma draws has allowed them to go 14 points clear at the top of the table with only nine games remaining.
Juve have fully capitalised on the capital outfit's constant slip-ups, rarely letting their form dip. They have recorded five successive victories across all competitions since they were angered by their first-leg loss to Fiorentina.
The most recent of those wins came on Saturday in the form of a comfortable 2-0 success at home to Empoli. Carlos Tevez opened the scoring with his 25th of the season before Roberto Pereyra made sure of the points late on.
Victory came at a cost for Massimiliano Allegri, though, as Arturo Vidal limped off. The Juve manager will be praying that the Chilean is not badly injured as Paul Pogba and Claudio Marchisio are already midfield absentees.
While the Turin outfit have dominated Italian football in recent years and are well on their way to a fourth successive title, the Coppa Italia has proved illusive and it has remarkably been 20 seasons since their last triumph in the competition.
Former Derby County and Middlesbrough striker Fabrizio Ravanelli was one of the scorers as Juve beat Parma for the trophy in 1994-95. Allegri will endear himself to the Juventus faithful, some of whom still need convincing, by ending the drought, but they have a task on their hands.
Recent form (all competitions): LWWWWW
Juventus's injury crisis in midfield could be solved by the return of Andrea Pirlo, who has not played in six weeks because of a calf strain. The 35-year-old playmaker is rated as 50-50 and Allegri may be tempted into gambling on his fitness.
Paolo De Ceglie, Martin Caceres, Romulo and Kwadwo Asamoah join the trio of likely midfield absentees, and so Pereyra could be rewarded for his scoring cameo as a substitute with a start at the Stadio Artemio Franchi.
Alvaro Morata, also used from the bench against Empoli, may get the nod ahead of Spanish compatriot Fernando Llorente as Tevez's strike partner, while Giorgio Chiellini should be recalled at the expense of Angelo Ogbonna in defence.
The hosts have lost three first-team regulars since the first leg, with Josip Ilicic, Manuel Pasqual and Stefan Savic all picking up injuries, so Montella is unlikely to deter too far from the side which bested Sampdoria.
Diamanti's strike should see him preferred on the wing to Joaquin, but Matias Fernandez and Nenad Tomovic could be recalled in place of Alberto Aquilani and Manchester City loanee Micah Richards. Alberto Gilardino may be included among the substitutes.
Fiorentina possible starting lineup:
Neto; Rodriguez, Basanta, Tomovic, Alonso; Badelj, Fernandez, Valero; Salah, Diamanti; Gomez
Juventus possible starting lineup:
Buffon; Bonucci, Barzagli, Chiellini; Lichtsteiner, Pirlo, Padoin, Pereyra, Evra; Tevez, Morata
Head To Head
Fiorentina's recent home record against the Old Lady makes this cup semi-final even more unpredictable. It really has been a mixed bag, from a 4-2 victory last season to a 5-0 drubbing in the 2011-12 campaign.
They have not lost either of their encounters this term, and a repeat of December's goalless stalemate will do just nicely for Montella's men as they hope to set up a showdown against either Napoli or Lazio.
We say: Fiorentina 1-1 Juventus
This one could go all the way to extra time and penalties, but if there is to be an aggregate victor in normal time then it might just be Fiorentina. Their threat on the counter will cause Juve problems and, if they can make it to the break without conceding, a spot in the final might just be theirs.