Stafford McDowall will captain the side and is in midfield alongside Northampton's Rory Hutchinson, who will play for Scotland for the first time since 2022.
Darcy Graham returns following his concussion against Fiji earlier this month while Arron Reed will be on the opposite wing after making his debut on this summer's tour.
Tom Jordan retains his place at full-back and is the only survivor from the team that started against the Springboks last weekend.
Johnny Matthews, a late call-up to the squad, is on the bench and is likely to add to his one cap against Romania in the 2023 Rugby World Cup.
Oyannax lock Ewan Johnson is the replacement second row while Kyle Rowe returns after missing the South Africa match through injury.
Scotland team to face Portugal
Jordan (Glasgow); Graham (Edinburgh), Hutchinson (Northampton), McDowall (Glasgow), Reed (Sale); Hastings (Glasgow), Horne (Glasgow); Bhatti (Glasgow), Harrison (Edinburgh), Hurd (Leicester); Craig (Scarlets), Samuel (Glasgow); Crosbie (Edinburgh), Muncaster (Edinburgh), Bayliss (Bath).
Replacements: Matthews (Glasgow), Sutherland (Glasgow), Millar Mills (Northampton), Johnson (Oyonnax), Douglas (Edinburgh), Dobie (Glasgow), Currie (Edinburgh), Rowe (Glasgow).