The South African-born No.8 succeeds Paul Tito as skipper of the Blues as the region enters a new era under the guidance of Phil Davies and back at the Arms Park.
Pretorius, a former student at Hartpury College, Gloucester, made his Blues debut against Connacht in 2009 and has become an increasingly influential figure since.
"It's a big honour to be appointed captain especially where we are as a team," said Pretorius.
"We've got a young team and we are building towards the future, it's a privilege to be part of it.
"Paul Tito and Xavier Rush were both players that I learnt from and both of them were phenomenal for the club.
"We've got a good team and a good group of young players. We haven't just got one leader we've got some good guys in the team who are all leaders.
"Someone like Josh Navidi talks a lot on the field, which is great, and that's where we want to do our talking this year.
"Everyone knows their jobs and knows their responsibilities, there's an attitude growing in the team where we are working hard for each other and pushing ourselves both mentally and physically.
"Having guys like Leigh, Gavin, Josh, Bradley and Daf just makes my job easier, knowing I have these guys behind me."
Pretorius has been a prominent figure in the Blues' pre-season preparations and Davies reckons the big ball-carrier demonstrates all the neccessary leadership traits.
"When I first came here we identified a couple of key areas of behaviour and the qualities we needed during the course of the season for us to have a successful year," said Davies.
"We had a session last week with the players where we asked them to identify the people who displayed these behaviours on the most consistent basis and Andries came out very favourably.
"He has a lot of respect within the playing group and within the staff for that matter.
"We've also picked vice captains who are Leigh Halfpenny, Josh Navidi, Bradley Davies, Gavin Evans and Dafydd Hewitt.
"We've got a strong leadership counsel for the season. I've also picked technical and tactical leaders around the scrum, the lineout, the restart, the breakdown and defence.
"I'm really pleased about it and anytime we need leaders on the pitch I feel we have them. It will give us strength in depth with regards to leadership.
"I think Andries will grow into the role.I made him captain out in South Africa for maybe obvious reasons and my discussions with him about rugby have been good.
"I'm not going to expect too much of him at the start with regards to technical and tactical leadership but that will grow with experience.
"He's got a big heart and respect of the players and that's important for any leader."