The ex-Parma man flourished after joining La Viola for almost 15million euros in 2008, going on to score almost 50 goals for the Tuscan giants.
But when his mentor, Cesare Prandelli, left the Stadio Artemio Franchi to take charge of Italy in 2010, Gilardino's form took a rapid nosedive and he struggled to make a difference upon joining Genoa last year.
But a loan spell at the Stadio Renato Dell'Ara has proved just the tonic for the former AC Milan forward, who made it five goals from five appearances thanks to a brace in a 4-0 victory over Catania.
Gilardino will already know if he has re-entered Prandelli's plans before kick-off in Tuscany, with the Azzurri boss set to name his squad on Sunday morning.
He told Gazzetta.it: "I spent three-and-a-half wonderful years in Viola colours and scored nearly 50 goals.
"I'll meet some old friends on Sunday, not least Luca Toni.
"I haven't heard from Prandelli since before the European Championships.
"I'm only thinking about Bologna at the moment but I haven't stopped thinking about pulling on the blue shirt again, and maybe even playing alongside Alessandro Diamanti."
Stefano Pioli's forward line may be in good shape but goalkeeper Gianluca Curci limped off the pitch against the Elefanti and is unlikely to travel.
While Gilardino enjoys a new lease of life in front of goal, Viola boss Vincenzo Montella is growing ever more concerned by his ailing attack.
Fiorentina are beginning to stutter having started brightly and Montella feels his men threw away a golden opportunity to punish Inter Milan last weekend, instead losing 2-1.
He said: "The opposition were never better than us but we didn't make the most of it, we didn't have enough shots on goal and I'm really unhappy about that."
The returning Mounir El Hamdaoui could partner Stevan Jovetic up front, while summer signing Stefan Savic could make his Fiorentina debut, given Gonzalo Rodriguez is suspended.