THE SWANS need to rediscover the "fine line" between attacking the ball and undisciplined aggression, veteran defender Leo Barry says.

Amon Buchanan accepted a four-week suspension for rough conduct last week, after Adam Goodes and Barry Hall copped bans in previous weeks.

"We always discuss it so it's an area we have let slip and hopefully for the rest of the season we can stay within the rules of the game," Barry said.

"It's just sort of crept in this season, so it's an area which we have to address.

"Everyone is really aware of it, the fact that you let your teammates down if you are suspended, so hopefully we've seen the end of it.

"Our guys must get back to really attacking the ball and still being aggressive towards the man, but it's a fine line [between] being aggressive and copping a few weeks."

The Swans have slipped to a 9-5 record, with one draw, after consecutive losses against Collingwood and Hawthorn.

"We do have a lot of guys who aren't at their best," Barry said. "And across the board our form has been inconsistent and there are quite a few areas ... last week we didn't make enough of our tackles. And it's just that little lack of intensity which is required every time we play.

"I think over the last three weeks, including the game against Melbourne our form hasn't been great."

The next few weeks shape as crucial for Barry's side, with games against Carlton, Adelaide and the Western Bulldogs in the next three rounds.

"We've tried to build up the last few weeks as really important games, so this is a must-win game for us against Carlton," Barry said.

"Their form's been okay, they've really stretched St Kilda last week but for us it's really all about getting back to the way we play and instilling a bit of confidence back into the team.

"So hopefully we can address those issues this week and return to playing the way we normally do this week against Carlton."