Competitive in the first half against Hawthorn last Friday night, the Swans fell away dramatically in a one-sided contest after the main break, leaving their flag defence hanging on a knife-edge.
Nine Swans have played every game this season, including midfielders Ryan O'Keefe, Josh Kennedy, Kieren Jack, Jarrad McVeigh and Luke Parker.
Coupled with the club's long injury list, it has some believing the workload is taking a toll.
One of the AFL's hardest runners, Hannebery had played every game before missing round 23 with bone bruising, and appeared a little restricted playing a run-with role on Isaac Smith in last week's first half.
But the 22-year-old insisted he felt 100 per cent before the game and believed a lack of concentration had been the Swans' main problem.
"I don't necessarily think we're tired," Hannebery said.
"The way we played the week before for four quarters (in a two-goal loss to Hawthorn) was pretty encouraging.
"Then the way we played that first half last week was really encouraging and we were unlucky not to be three or four goals up the way we were using the ball, and we butchered it in the second half.
"We don't think it was a tiredness thing, we think it was more of a concentration issue, which was un-Sydney-like really.
"We want to make sure we correct that this week."
Accustomed to being tagged himself this season, Hannebery's role on Smith was his first run-with assignment for 2013.
While the dangerous Hawk didn't have a huge impact, he was able to get free of the young Swan at times, while Hannebery's 13 disposals at 53.8 per cent efficiency were well down on his season averages of 26 and 70 respectively.
His coach John Longmire, a huge admirer of how the courageous youngster plays his football, is backing Hannebery and the rest of his midfield to bounce back against the Blues.
"'Hanners' had a role on Smith in the first half and Smith played OK, he had six possessions to half-time," Longmire said.
"Hanners had a specific role and we changed it after half-time, probably due to the scoreboard and changing a few things.
"But we're really confident in Dan Hannebery's ability to play well and he epitomises our two-way football at its best, (along with) Kieren Jack, Ryan O'Keefe, Josh Kennedy.
"That's what we'll try to do this week."
Hannebery contests his 100th game on Saturday, a milestone which has come around quickly since his debut in round 16, 2009.
His seven matches that season came while he was still attending school at Xavier College in Melbourne, something he calls "a pretty surreal experience".
"I was going to school Monday to Thursday, then training late in the week and playing and going back down for school."
A runaway winner of the 2010 NAB AFL Rising Star award, Hannebery has improved his output every season, and was named in this year's 40-man All Australian squad for the first time.
The Swans are now finding themselves in the familiar position of being written off by some, but Hannebery knows what it will take for them to start firing once more.
"We think as a whole group we can work better together," he said.
"We probably didn't help the defence out last week, Hawthorn took too many marks and had too much uncontested footy and their forwards took easy lead-up marks and kicked goals quite easily.
"We just need our midfielders working harder together and forwards trying to stop the opposition's ball movement and just trying to maintain that effort we had in the first half.
"That'll go a long way towards winning the game and getting our confidence back – and we know anything can happen from there."
Twitter: @AFL_JD
