On the eve of the season, Mark Harvey lost the core of his backline.

Fellow Line Coaches Hayden Skipworth and Guy McKenna were in a similar position.

Players expected to hone their craft in the VFL and maybe get a taste of senior footy were suddenly tasked with key roles on the biggest names in the game.

Harvey has used a combination of experience, VFL talent and players looking to make the most of a second chance in the AFL to reassemble the Dons defence.

Fremantle, Richmond, Brisbane and Gold Coast have all conceded more points than the Bombers this season, despite the Dons missing such key personnel.

Harvey told Bomber Radio his new look defence is becoming more comfortable playing alongside each other by the week.

“They’re still working out each other, they’re still forming an understanding of how each other play, they’re starting to trust each other a lot more and get their positioning on how they should defend right early,” he said.

“The backline is evolving.  They’ve been defending quite well under difficult circumstances.”

Anthony McDonald-Tipungwuti has been a key figure in the Dons defence so far this season.

After graduating from the Bombers VFL program, the rookie-listed player has featured in every match so far and is averaging 17 possessions per game.

“He’s been instrumental,” Harvey said.

“The crowd light up every time he gets the ball.

“He’s just different because he’s strong in the contest, he’s got that low centre of gravity but when he gets the ball, he really hurts the opposition and we’re starting to see the excitement of the run and carry and the draw and then getting out of situations which he shouldn’t.

“On top of that, he’s defending a dangerous small forward for the opposition.

“It’s still work in progress, but we’re really happy with the way that he is going.

“Once he gets these other players around him, wow, you’re going to see something special." 

Michael Hartley has been given the task of taking the best key forward each week and even kept Tom Hawkins goalless in round four.

Matt Dea has also been a regular in the backline after signing with the Club just a few weeks before the start of the NAB Challenge.

He was set to play in the VFL after being delisted by Richmond after 31 games.

“I think it’s the first time that he’s had continuity in playing in senior games and with that has come confidence,” Harvey said.

“He took 15 marks last week as a defender and that’s nearly unheard of unless you’re getting those sideways kicks or backwards kicks, but a lot of those were intercept marks.

“We’re starting to see his kicking evolve too.

“He’s a tough competitor too. I would think that at his age (24) he would certainly be an option moving forward for the draft coming up."

Mark Baguley has continued his good form of recent seasons, though he has also spent time in the forward half.

Baguley and James Kelly are the senior figures in the Dons defence.

The three-time premiership-winning Cat leads the Bombers for intercept possessions and is ranked fourth for disposals.

“Kelly is interesting, once again he has played very well,” Harvey said. 

“I think he has been excited by what he has seen in and around the Club and I wouldn’t be surprised if he wanted to play on again next year.”