Originally described as a "minor strain" that would keep the 22-year-old out for a week, it has now turned into a month-long injury.
Pittard hasn't played since his impressive 22-disposal, eight-mark performance against Gold Coast in round four.
The Power face Carlton on Sunday and Pittard was set to be assessed at training as he had been in the lead up to the previous three games.
He'll still be put through his paces, but as much as senior assistant Alan Richardson would like Pittard in his side, he conceded it probably wouldn't happen this weekend.
"It's fairly unlikely that he'll play, very unlikely at this stage," Richardson told AFL.com.au.
"It's concerning because he's a talented player that makes us a better team. It'd be nice to have him out there… it's frustrating from a team and coaching perspective.
"He's a young guy, he's not heavily built, he's still building up his own body and his own durability.
"It's not a long term concern for us, we just think this is part of his development."
Harry Thring is a reporter for AFL Media. Follow him on Twitter: @AFL_Harry.
