Coach Rob Moffat said: "The Selkirk Sports are a good chance for us to look at a group of players who are involved in our Scotland 7s training squad ahead of the IRB Sevens series which starts in December in Dubai.
"It is also an opportunity for these players to stake a claim in a competitive situation. I don't want to look at this side as a development team and it's certainly not lacking experience. This is a really good opportunity for all of us and I'm looking forward to it.
"Selkirk Sports is an excellent tournament and with the Border Reivers' players coming along to show their support and mix with the crowd, it will be a fantastic day," he added.
Moffat has drafted in Cartha Queens Park winger Andrew Noble for his first taste of sevens in a Thistles' jersey. Scotland 7s and Newcastle Falcons winger Cameron Johnston was due to be involved on Sunday but he will instead remain in Newcastle to play for the club, thus opening the door for speedster Noble.
The Scottish Thistles kick-off the tournament against Berwick at 1.30pm. The remainder of the draw is: Howe of Fife v Hawick, Gala v Langholm, Selkirk v Peebles, Haddington v Royal Scots, Edinburgh University v Melrose, Jed-Forest v Duns, Kelso v Watsonians
SCOTLAND THISTLES SQUAD
- Oli Brown (Boroughmuir and Scottish Institute of Sport) CAPTAIN
- Richard Vernon (Stewart's Melville FP)
- Roddy Deans (Heriot's)
- John Barclay (Glasgow Warriors and Scottish Institute of Sport)
- Matt Coupar (Edinburgh Accies)
- Tane Jericevich (Aberdeen GSFP)
- Steven Duffy (Glasgow Hawks)
- Nick De Luca (Edinburgh Gunners and Scottish Institute of Sport)
- John Houston (Heriot's)
- Andrew Noble (Cartha Queens Park)