Lumumba, who joined the club during last year's trade period after an unhappy ending to his time with the Magpies, has impressed so much through the pre-season that he was elevated into the Demons' leadership group, officially unveiled on Tuesday at the MCG.

Lumumba had been seen by some at Collingwood as a disruptive figure in his final years there, having been involved in internal club disputes. Even his manager had admitted the dashing half-back needed to communicate better "how he expressed himself going forward".

However, Roos said the 2010 premiership defender, who had spent the first half of last season in the midfield, had been a diligent performer during the summer slog.

"I just think it shows what high standards he does have," Roos said. "We had no pre-conceived ideas for Heritier before he came, other than what we have seen on the footy field.

"I guess there is a lot of rumours and talk about Heritier, which surprised me to be perfectly frank. I think the players would agree we have seen nothing but high standards, nothing but a guy that has been compliant and wants to drive the group.

"For him to be named [in the leadership group] in such a short space of time gives you an idea of how highly regarded he is already by the guys at the Melbourne footy club."

The Demons, having won just four matches last season, will need Lumumba to provide plenty of drive if they are to, in the words of skipper Nathan Jones, again become a "great club".

In announcing Jones would be the stand-alone skipper, the Demons revealed he would be assisted by new vice-captain Lynden Dunn, who was fighting for his future only a couple of years ago, while Daniel Cross, Chris Dawes and former co-captain Jack Grimes would also form part of an experienced leadership group.

"I think it's a really good mix of guys that understand how difficult it has been, but also some guys who have had some real success who can continue to raise standards around here," Roos said.

Gone from last year's leadership group are Mitch Clark, Colin Garland, Jack Trengove, recovering from foot surgery, and James Frawley.

The Demons had one of the youngest leadership groups under former coach Mark Neeld but that has now changed considerably, with Dawes and Lumumba premiership players with Collingwood and Cross, the former Western Bulldog, a veteran of 227 matches.

"I am really confident and believe the guys that are in this leadership group will guide the footy club in the right direction. We will continue to raise the bar and raise the standards as leaders as much as we can and play a role for the team," Jones said.

"I am really confident with the current list we have got and the direction the footy club has taken [that] we will be back to being a great footy club again and winning games of footy consistently and playing a brand of footy that excites our fans and our members makes them want to support us, and repay some of that faith and the loyalty they have shown over a lean few years."

The bruising Jones has already been one player to repay that loyalty, having claimed three consecutive best and fairest awards, and last year inking a four-year contract extension, ensuring he remains at the club until the end of 2019.

Dunn, 27, said a settled role in defence had helped him become more of a leader.

"It's really helped me focus in on game day and narrow my focuses. I think I have always had natural leadership qualities but it's taken me a while to bring those out," he said.

Roos, himself looking fit and fresh ahead of his second season in charge, praised Dunn's efforts.

"He is certainly one player, when you come from another club, not knowing a lot about the internal workings of the Melbourne footy club, you probably see Lynden as a journeyman who has played in a lot of different roles. You really don't appreciate how much time and effort [he puts in] and how much he is respected by his peers," Roos said.