Mayes was always touted as a top-10 draft pick and with Port Adelaide locked with the number seven selection, was a big chance of staying at home.
However when the impressive Ollie Wines slipped to number seven in Thursday night's NAB AFL Draft, Port pounced, leaving Mayes to be snapped up by the Lions with the following pick.
Lions national recruiting manager Rob Kerr and his team had eyed off the 187cm forward-turn-midfielder all year and were rapt he fell their way.
Quietly spoken Mayes said although draft day was nerve-racking, he was pleased to be joining Michael Voss' team.
"I think Ollie Wines is going to be a very good player for the Port Adelaide footy club but I'm very thankful for the opportunity I've been given and I'm very grateful for that," Mayes said.
"I'm looking forward to getting there Monday and just giving it a crack through pre-season. I don't want to look too far ahead."
The 18-year-old was an under-18 All Australian in 2011 and was impressive in the senior ranks for North Adelaide in the past season.
Kerr said he envisaged Mayes starting his career in the Lions' forward line before evolving into a tallish midfielder.
"He's a very good kick, that helps us in terms of delivery, but we feel he has the ability to move into the midfield after he develops his footy," Kerr said.
"He'll have a big frame, he's quite quick and he shows signs of being able to get in and out of the game as well and will be a bit of a weapon with his versatility."
Assistant coach Mark Harvey said Mayes would be introduced slowly to the club's training in the lead up to Christmas.
"He's going to hang around Simon Black for the first couple of weeks," he said.
New Lion Sam Mayes with his proud parents on Friday. Picture: AFL Media
"Sam is pretty elite in the running area so I'm assuming it won't take him long to join in with the pack.
"He'll probably be tested in January and February physically and we'll see how he progresses from there. We don't put any expectation on him though."
Michael Whiting covers Brisbane Lions news for AFL.com.au. Follow him on Twitter: @AFL_mikewhiting
