The pair have re-signed on new two year deals, tying them to the club until the end of 2021.
Rioli, 21, has played 55 games for Richmond and was thrilled to carry on his family name.
“My grandfather played here and I want to play as many games as possible at this club so I’m rapt to be on board for a couple more years,” Rioli told the club website.
“I hope to continue what I’ve brought to the club, and to try and be a leader to the younger boys coming through.”
Vlastuin, 24, has totalled 118 senior games in the yellow and black and is being dubbed as the club’s next potential skipper.
“When the call came through I was really excited, I didn’t want to go anywhere so it’s good to get it done before the season starts,” Vlastuin told the club website.
Tigers GM Neil Balme was ecstatic to see both Rioli and Vlastuin put pen to paper.
“Both Daniel and Nick are important players for our future, and we’re really pleased they both see Richmond as their home,” he told the club website.