Petrenko looked to hyperextend his shoulder just before the final siren and was in tears after the game.
On Saturday morning the 22-year-old forward jokingly tweeted that his tears were those "of joy about making a prelim final" and Reilly said he'd back his teammate to perform even if he carried an injury into the penultimate game of 2012.
"He's up and about today, [but] we won't find out (how bad the injury is) until we get the scans results," Reilly said.
"He's a tough hombre, Pup. We rely on his defensive pressure up forward and if he doesn't play this week he's going to be sorely missed.
"With shoulders, you could play with shoulders, so hopefully Pup does everything right and is up for selection this week."
Defender Sam Shaw was also injured in Friday night's come-from-behind 10-point win, hurting his hamstring in the first quarter.
Shaw took no further part in the game and post-match Brenton Sanderson conceded he would again need to reshuffle his defence as he did when Daniel Talia broke his arm against the Sydney Swans.
While Shaw is unlikely to play against the Hawks, Reilly was confident he'd provide good support during the week.
"Shawry's a good kid and he'll bounce back, you never know, it might not be too bad," Reilly said.
"He's got a good character about him and he'll be up and about this week for us."
On Friday night the Crows were ignited by a pumped-up Taylor Walker, who's clutch goal on the half-time siren saw the home side boot eight second-half goals to four.
Walker celebrated each goal with true passion and Reilly said it wasn't just the crowd who lapped it up.
"The goal before half-time was uplifting and got the crowd involved and it got the boys up," he said.
"He's a bit of a barometre for us in how we're going…the way he celebrates is outstanding and we want him to keep doing it."
Hawthorn livewire Cyril Rioli looms as one of Adelaide's toughest opponents next Saturday and Reilly said he, like Walker for the Crows, was a barometre for the Hawks.
Reilly tipped Michael Doughty to get the job on Rioli.
"He'd run circles around me before I even saw him, I need to get on the blokes that are a bit slower and the blokes that are a bit more to my ability " Reilly laughed.
"'Dogga' (Michael Doughty) played on him last time [and] did a pretty good job, Dogga did an outstanding job on (Hayden) Ballantyne last night so I'm sure he'll be the man putting his hand up."
Harry Thring is a reporter for AFL Media. Follow him on Twitter: @AFL_Harry.
