The external build-up to Sunday's clash between Steven King's revitalised Demons and the unbeaten Suns has been as much about who won't be there as who will.
Petracca, who exited the Demons after a tumultuous 18 months during last year's trade period, was to have been the central figure.
But a hamstring injury sustained in a win over Richmond last month has sidelined the star midfielder for multiple weeks.
Petracca had been in red-hot form, best afield in his first two outings with the Suns before he was struck down.
"It's a shame. It would've been great to play against Christian," Langdon told AAP.
"But he's had an unbelievable start to the year, so it might benefit us that he's actually not playing."
The departures of Petracca and 2021 premiership teammate Clayton Oliver, and Jack Viney's long-term achilles injury, has opened the door for a new-look Melbourne engine room.
Caleb Windsor and Tom Sparrow have taken on greater roles, and off-season recruit Jack Steele has added experience, while Trent Rivers was surprisingly dropped after being touted as one to step into the void.
But none have seized the opportunity quite like Kysaiah Pickett, who has relished greater midfield time with some career-best numbers, averaging 22.7 disposals, 4.3 clearances and 5.3 tackles per game.
The explosive 24-year-old was the match-winner with a brilliant second-half performance in the thrilling comeback win over Carlton last round, which gave the Demons a 2-1 start under new coach Steven King.
"He's certainly taken his game to another level," Langdon said.
"He's such a terrific player and he's focusing more and more on his midfield craft, and working out how the best midfielders in the competition go about it.
"And we know what he can do when he goes forward - that's kicking goals."
Melbourne have recalled Daniel Turner and veteran forward Jake Melksham, with Changkuoth Jiath (calf) and Paddy Cross (thumb) both out.
Petracca and suspended forward Bailey Humphrey are huge outs for the Suns, but coach Damien Hardwick welcomes back Brownlow Medal winner Matt Rowell from injury to bolster his midfield.
Key forward Jed Walter and Lachie Gulbin will play their first games of the season and Alex Davies has been dropped.
