Powell was seen to be in the mix for a Round 1 appearance despite suffering a fractured and dislocated ankle in Round 14 last year.
The 23-year-old had miraculously managed to link up with teammates for key drills over the course of the pre-season after the horrific setback initially placed his 2023 prospects in doubt.
However, Powell's chances of lining up against Sydney for the club's season opener now look to be in doubt once again, with a grade three hamstring tear placing the young defender back in the Suns' casualty ward.
"It's a fairly substantial one," Campbell told AFL.com.au of Powell's latest setback.
"We all have a fascination with round one, and we understand that, but that's not the goal."
Powell was among a contingent of Suns players that saw their 2022 campaign cut short due to injury, with Lachie Weller, Ben King, Joel Jeffrey and Charlie Ballard all sustaining season-ending knee injuries.
All four players are expected to be in the frame for Round 1 selection, with Weller well ahead of schedule and a chance to make a stunning early-season return.
"The high-performance and medical guys would say he's come back as well as they've seen," Campbell said.
"He's going really well. We're holding him back a bit, but he'll be (available) around the start of the season ... whenever he's right to go.
"If it takes four more weeks, it takes four more weeks, but if he's right to go, we'll play him."
Defender Connor Budarick remains out of action as the new season nears, with his recovery from an ACL injury keeping him sidelined for the first half of the 2023 season.
Gold Coast will open their 2023 campaign against grand finalists Sydney at Metricon Stadium on Saturday, March 18.