The fight is on the undercard of Strikeforce's Heavyweight Grand Prix at Cincinnati's U.S. Bank Arena.
The main card sees Josh Barnett (27-5) against Russia's Sergei Kharitonov (18-4) and Daniel Cormier (8-0) against Brazil's Antonio (Bigfoot) Silva (16-2) in the tournament semifinals.
Just 21, Mein has already compiled a record of 21-7 in mixed martial arts. He started fighting professionally at 16 with bouts coming quickly thanks to his father Lee Mein, a promoter and fighter in his own right.
Jordan Mein (pronounced Mee-IN) fought six times in 2010 and Saturday will be his fifth outing in 2011.
He is 9-1 during that period and coming off wins over Dream champion Marius Zaromskis and former UFC veteran Josh Burkman.
"I've taken it a step up every time," said Mein. "I hope to continue to do that in the future. So we'll see how this goes."
Mein won a decision over Zaromskis despite dislocating and breaking a toe — he launched a kick that was blocked by an elbow — in the first round.
Santos (18-14) is coming off a January loss to former Strikeforce champion Nick Diaz and is 4-6 in his last 10 fights. Prior to Diaz, the Brazilian beat Zaromskis.
"He is a good fighter but he has not been tested yet," Santos says of Mein on the Strikeforce website. "He has not taken many punches to the face yet in his career. I am going to test him."
The 32-year-old Santos is married to Strikeforce women's 145-pound champion Cris (Cyborg) Santos.
Mein trained in his native Lethbridge with help from San Diego jiu-jitsu instructor Roy Harris and fellow Alberta-based UFC fighters Jason (The Athlete) MacDonald and Nick (The Promise) Ring. Calgary lightweight Brad Cardinal was also in camp.
He expects Santos to come right at him, with the fight going "all over the place."
"He likes to stand as well, but it wouldn't be surprising if he shot for some takedowns," he said. "But I'd do the same. I'm here to fight everywhere and my goal is to beat him up in all areas of the game, whether it be standing or on the ground.
"I think he's going to come out hard and be aggressive like he usually is. We'll see how it goes. ... He'll be right in my face, I'm sure. And I'll be right there waiting."
Mein normally walks around at 180 pounds, which makes for a manageable weight cut. He expects Santos to be bigger on the night but he's not concerned.
"He obviously has to make the 170(-pound) mark so it's all good for me, As long as he steps on the scale at 171 (fighters are allowed a one-pound leeway in non-title fights), it's all good."
It's the first fight in the U.S. for Mein, but he says he has been able to escape the spotlight thanks to fighting on the undercard. He's just happy to be there.
"It's an honour to be on this card really," he said. "I'm just excited to fight and then be able to watch the rest of the card."
He's be cornered by his father, fellow fighter Brandt Dewsberry and trainer Steve Bergeron.
Strikeforce's heavyweight tournament has taken a few unexpected turns with Silva defeating Fedor Emelianenko and Overeem being released (only to sign with the UFC, which owns Strikeforce).
Cormier came in as Overeem's replacement in the tournament.
Also on Saturday's card, middleweight champion Ronaldo (Jacare) Souza takes on Luke Rockhold. Former light-heavyweight title-holder Muhammed (King Mo) Lawal faces Roger Gracie.