Brent Renouf has been brought into the side for his first game of the season.
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Lobbe had proven a key player for the Power in 2014 but would still have had his work cut out for him against giant Dockers ruckman Aaron Sandilands.
Power coach Ken Hinkley said on Friday that it was necessary to shark Sandilands' taps given his size and ability.
Lobbe trained on Friday but the club felt it a risk to play him on Saturday given it had the bye next weekend, offering the 23-year-old an extra week to recover.
"Matthew has some minor calf soreness at the moment, we're just managing him," director of coaching Shaun Hart said.
"He trained yesterday but he didn’t get through to a point where we felt it wouldn’t be a risk to play him.
"He’s had probably the biggest load of the group this year and we didn’t feel he was ready to play this game."
Twitter: @AFL_Harry
