Townsend has rung the changes following last weekend’s defeat to South Africa, with Tom Jordan at full-back the only survivor from the team that started against the Springboks.
Freddy Douglas, 19, could become Scotland’s youngest male Test player in more than 60 years if he is used from the bench.
The Portuguese will play their first international away at a top-tier nation, with around 60,000 fans expected at Murrayfield.
“I thought they were one of the most exciting teams to watch in the World Cup,” Townsend said.
“They moved the ball wide, they were accurate, they were cohesive and they got some good results – beat Fiji, drew with Georgia, pushed Wales really close. So we’re expecting that level of performance from them.
“They may not have played teams like Wales, Fiji and Australia since the World Cup, now they have a big opportunity this weekend to play a Six Nations team. So we expect that ambition, that accuracy and a really tough test match.”
