Ladhams, who joined the Swans from the Power this season, gifted his former side two goals in two minutes in a horror period at the Adelaide Oval.
Port Adelaide upset Sydney 12.10 (82) to 8.11 (59) to record its sixth win of the season.
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Moments after being pinged for throwing Darcy Byrne-Jones to the ground off the ball, Ladhams found himself in trouble again.
The 24-year-old threw Ollie Wines to the ground, and then punched him in the midriff, resulting in a downfield free kick to the home side.
Charlie Dixon slotted the goal and Swans coach John Longmire immediately hooked Ladhams.
“It’s what you can’t allow to happen,” said four-time premiership winner Jordan Lewis on Fox Footy.
“One, you’re fighting the crowd, you’re fighting the momentum in the game at the moment and yet you give away two really silly free kicks that have ended up directly in opposition goals.
“He’ll probably spend another week on the sidelines, as well. The tackle gets performed, that’s all that needs to happen, but then you see the swinging of the right arm.
“That is just a brain explosion.”
Brownlow Medallist Mark Ricciuto noted that ill discipline may have been behind Ladhams’ departure from the club at the end of last season.
“That might just confirm the reason why they pushed him out of the club,” he said.
“Why would you do that? Why would you do that to your ex-captain and former teammate?”
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