Key forward Joel Amartey is the latest Swan serving a three-week ban for rough conduct after his bump on Jordan Boyd left the Carlton defender concussed.
Justin McInerney was handed his second suspension this season for a separate high hit on Jack Silvagni in their 16-point win over the Blues.
The Sydney winger had already sat out three matches in 2025 for a bump on Brisbane Lions defender Brandon Starcevich.
Lewis Melican is also serving a three-game ban for striking GWS opponent Toby Bedford, and will be eligible to play after this weekend's MCG clash against Melbourne.
The Swans lead the league with suspensions, with their players serving three more weeks than Hawthorn (seven).
Asked if his players were battling with technique rather than discipline, Cox said: "It's probably a little bit of both.
"The players need to be aware of what they can and can't do, and then the technique, they have to train that.
"Whether it's arms out, not shoulder in. Try and tackle, that's probably the first thing that we always say, instead of bump.
"Players know now that if you're doing that and any collision, you're sitting on the sidelines.
"The bump and any contact you do make with the head, you're a high possibility of being suspended for a number of weeks.
"We need our best players playing footy, so they were made aware that we don't want to do that as a football club."
Sydney will also lose Aaron Francis after the defender suffered his second concussion this year, joining an already lengthy injury list.
But Cox expects to regain captain Callum Mills if he passes training later in the week, while key forward Hayden McLean and midfielder Taylor Adams are also options.
Mills marked his first game back from a foot injury by finishing with one goal, 20 disposals and three clearances in the VFL, while Adams took 30 touches.
"(Mills) has got one more session. If he gets through the session, he's playing," Cox said.
"That's probably the great thing about Callum now. He played extremely well in the restricted minutes that he had on the weekend.
"We've also got to understand Callum hasn't played a lot of AFL footy the last two years, so the expectation is for him to come and contribute to the football team, not to be the best player on the ground."
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