The 17-year-old flanker, who is from Owaka and boards at Southland Girls' High School, will start in the No 7 jersey against undefeated Canterbury.
Mason has ridden a steady wave of success the past two years.
In 2012, she was the first female inducted into Peter Skelt's Rugby Southland Academy, a programme which sees her train twice a day when she is in Invercargill.
''It's there to give you advice and try to keep you on track. There are nutritionists, strength and conditioning advice, just extra help to get to where you want to go,'' Mason said.
The talented flanker played three games for Otago last year and is working her way into the regular starting line-up.
Her commitment to the table-topping Spirit requires her to be home-schooled on Thursdays and Fridays.
''The teachers are really understanding . . . they give me work to do when I am away and fit my assessments around whether I'm there or not.''
Mason trains in Invercargill with the academy from Monday to Wednesday, before catching a bus to Dunedin on Thursday to make Spirit training.
She then returns south on Sunday after the weekend's game to continue the routine.
Mason, who plays club rugby for Otago University and helped Southland Girls' finish third in the top four schools competition in Rotorua earlier this month, is enjoying the challenge of sometimes playing against women twice her age.
''It's a good step up, but that is good. You know where you stand and it's good to see where you fit into the picture and you can only move up the grades,'' she said.
Otago has made an almost perfect start to the national provincial competition, winning its first four games and only missing out on a bonus-point win last week in Napier.
However, the Spirit will need to overcome a tough stretch in the final five weeks of round robin competition to make the final.
After hosting Canterbury tomorrow, the Spirit will have a week off, before playing Waikato at the University Oval.
It will then play defending champion Auckland away, before wrapping up the regular season at home to Manawatu.
With no semifinals, Otago must finish in the top two to make the final. After the Spirit hosted Auckland at Forsyth Barr Stadium in 2012, tomorrow's game against Canterbury will be just the second Otago has played under the roof.
''It will be my first time in the stadium,'' Mason said.
''I've played in Carisbrook but I haven't had a chance to get in the new stadium yet. They [Canterbury] are real tough and they are probably one of our tougher opponents. And there is the rivalry thing, neighbours and all.''
Canterbury won the preseason match between the sides 27-5.
- Robert van Royen
Otago Spirit v Canterbury
Forsyth Barr Stadium, tomorrow, noon
Otago: Sheree Hume, Summer Van Loenhout, Greer Muir, Michaela Baker, Kristina Moata'ane, Victoria Subritzky-Nafatali, Megan Manson, Angie Sisifa (captain), Georgia Mason, Rebecca Todd, Epe Elisara, Michaela Smith, Gemma Tuhega, Lucy Emery, Phillipa Love. Reserves: Zoe Whatarau, Sophie Kuper, Kelly Whitten, Julia Gorinski, Madeleine Finch, Deirdre Roberts, Claire Richardson.
Canterbury: Tara Horsnell, Keshia Grant, Lucy Anderson, Nicola Hoole, Lucy Ryan, Charntay Poko, Kendra Cocksedge, Whitney Hansen, Estelle Uren, Laura Buckingham, Jess Hansen, Leysa Matity, Stephanie Te Ohaere-Fox, Kristina Illston, Abby Ley. Reserves: Molly Wright, Jess Fibbes, Mackenzie Rossiter, Vicki Campbell, Claire Smith, Keilamarita Pouri-Lane, Elizabeth Pera.
