From the AFL website:"Given the improved maturity of the team, we believe a five-player leadership group is a sufficient representation of the playing list," coach Damien Hardwick told the club's website.
"We are proud of the way Trent embraced the captaincy in his first year, and we're confident he will continue to be a strong leader on and off the field, along with Brett as vice-captain.
"Troy Chaplin's inclusion in the leadership group highlights the impact he has had on the group in a short period of time, and is a reflection of his strong character, and qualities as a person, which were things we identified when we recruited him to the club.
"We want to develop a culture that encourages every player on the list to be a leader in some way, and our challenge as a football club is to help them do that."
Riewoldt is set for a role slightly higher up the field this season, while Grimes is hoping for his first uninterrupted season since he was drafted.
The 22-year-old has played 26 games in four years, with persistent hamstring injuries derailing him early on and a fractured foot hampering him in 2013.
He missed last week's Australia Post Community Camp in Warnambool because of hamstring tightness, but had put together a decent pre-season before that.
http://www.afl.com.au/news/2014-02-11/riewoldt-out-as-leader