Only winger Kyle Steyn and centre Chris Harris retain their places from last week's bonus-point 45-17 win over Tonga to face lowly Romania in Lille on Saturday.
"There's players that deserve an opportunity to play at this World Cup," Townsend said.
"With a six-day turnaround we wanted the freshest possible team to build on that victory over Tonga," he added.
Lock Grant Gilchrist replaces Jamie Ritchie as skipper with Townsend choosing to rest front-line players such as fly-half Finn Russell before Saturday week's match with table-topping Ireland.
Gilchrist was vice-captain in their tournament-opening loss to South Africa and has led his club Edinburgh as well as his country in the past.
"He brings a lot of our emotion," Townsend said.
"He's going to make sure we're primed and ready for this," the former Scotland and British and Irish Lions fly-half added.
Flanker Ritchie was concussed in the victory over the Pacific Islanders in Marseille.
Matthews' 'pace'
Tight-head prop Javan Sebastian makes his World Cup debut as does Russell's replacement Ben Healy with hooker Johnny Matthews set for his first Scotland appearance off the bench.
Matthews replaced Stuart McInally, who suffered a neck injury, in Townsend's squad earlier this week.
"It's been a bit of a whirlwind for him. The temperature change is the biggest shock," Townsend joked from Scotland's training base in Nice, where the temperature was 26 degrees Celsius (78 degrees Fahrenheit) on Thursday.
"It's a great game for him to come off the bench and show his strengths which are around the set-piece, in particular the speed and pace he brings on the ball.
"I'm sure he'll get opportunities to carry on the weekend."
Townsend's side need to beat Romania, 14 places below them in the world rankings, ideally with a bonus point to keep their hopes of reaching the quarter-finals alive.
"We can't take them lightly," Townsend said.
"A lot of what we'll do will be about us, the standards we set in training, where we believe we are as a rugby team, they have to come out over 80 minutes this weekend," he added.
If South Africa beat Tonga on Sunday, the Scots will then need to overcome tournament favourites Ireland in their final Pool B match in Paris next weekend.
Scotland (15-1)
Ollie Smith; Darcy Graham, Chris Harris, Cameron Redpath, Kyle Steyn; Ben Healy, Ali Price; Matt Fagerson, Hamish Watson, Luke Crosbie; Grant Gilchrist (capt), Sam Skinner; Javan Sebastian, Ewan Ashman, Jamie Bhatti
Replacements: Johnny Matthews, Rory Sutherland, WP Nel, Scott Cummings, Rory Darge, George Horne, Blair Kinghorn, Huw Jones
Head coach: Gregor Townsend (SCO)
