THE SYDNEY Swans' round 19 win over Carlton showcased their improved midfield balance this season.

As we've come to expect over the Paul Roos and John Longmire coaching eras, the Swans' midfield output against the Blues was founded on their grunt work at stoppages.

There the likes of Dan Hannebery, Jarrad McVeigh, Josh Kennedy and Kieren Jack led the Swans to a 38-33 win in the clearances and a 136-129 win in contested possessions.

But the Swans have added an electrifying outside edge to their play this season that has helped put them a game clear on top of the ladder after round 19.

Its most obvious exponent has been emerging speedster Lewis Jetta, who again gave the Swans blistering run and carry against the Blues, taking an equal team-high four bounces.

But Jetta's run was complemented by that of Jack (two bounces) and Rhyce Shaw (four) off half-back.

After Sunday's game, Swans co-captain McVeigh, who racked up 28 possessions against Carlton while holding star Blues midfielder Murphy to 24, said his team's midfield mix had improved a lot this season.

"The likes of 'Joey' Kennedy, Luke Parker and Ryan O'Keefe and Jude Bolton get in and set up 'Jetts' (Jetta) and 'Kizza' (Jack), who are then hard to stop with their skills going forward," McVeigh said.

"I think we've improved a hell of a lot in that area.

"It's always a focus for us to win that ball inside and if we do win that footy it helps our outside run.

"I thought we did that well today and we worked both ways as a group which was good."

The Swans' more potent midfield has been one of the keys to their impressive surge up the ladder this season.

McVeigh says it is too early to tell just how much the Swans, who finished sixth last season and have not finished in the top four since their 2006 Grand Final appearance, have bridged the gap to the competition's powerhouse teams.

"We've done nothing yet. You can only really improve once you get in a final," McVeigh says.

"We have improved as a group no doubt, but when the big stuff starts that's when we'll find out how good we are."

Still, McVeigh is confident of the Swans' prospects and looking forward to its upcoming home and away encounters with third-placed Collingwood (round 20, ANZ Stadium), fourth-placed Hawthorn (round 22, SCG) and reigning premier Geelong (round 23, Skilled Stadium).

"We've played a few of the top teams this year and we've beaten teams like Hawthorn, Geelong and West Coast, so we know we can compete," McVeigh said.

"We're playing some of those teams in the next few weeks and we can't wait.

"Obviously Collingwood next weekend is going to be a massive test. We haven't beaten them for a while (the Swans have lost the teams' past 10 games) so hopefully there's a big crowd in Sydney and we can put in a really good performance."

McVeigh is hoping veteran midfielder Jude Bolton will be part of the Swans' push to the finals and subsequent September campaign.

Bolton hyper-extended his left knee in the third quarter against the Blues after planting his foot awkwardly following a hurried kick out of defence. Bolton was subbed out of the game soon afterwards amid fears he had damaged his anterior cruciate ligament.

Although the extent of Bolton's injury won't be known until he has scans on Monday, McVeigh is keeping his fingers crossed.

"He's been in really good form. I'm not too sure what he's done but hopefully it's something minor," McVeigh says.

Nick Bowen is a reporter for AFL.com.au. Follow him on Twitter: @AFL_Nick