The 23-year-old has been training in the role for several weeks in order to widen his repertoire at both club and test level. Fellow Test lock Luke Romano will slot into Barrett's spot in the second row, while Mitchell Dunshea is likely to make his debut from the bench.
"A great athlete, clear on his role, gives us another lineout option," Robertson said of Barrett. "For him, it's something he can add."
Elsewhere, openside Matt Todd and winger Digby Ioane will step back into the fold, after recovering from a calf strain and finger injury respectively.
Halfback Bryn Hall has been switched out for Mitchell Drummond, while stalwart Tim Bateman has stepped into the midfield and Manasa Mataele moves to the bench.
Robertson said he expected a challenge from the Force, who are coming off the bye and have historically lifted their game against the Crusaders.
The Christchurch-based side have won four of their last five games against the Force, but never more than two in a row. They were only able to scrape over the line with a 20-19 win in Perth last year.
"Teams coming off the bye traditionally have a little more variation in their game and their play," Robertson said. "They're a tough side and they've shown it with their results, and how close their games have been."
CRUSADERS: David Havili, Digby Ioane, Tim Bateman, Ryan Crotty, George Bridge, Mitchell Hunt, Mitchell Drummond, Jordan Taufua, Matt Todd, Scott Barrett, Sam Whitelock (c), Luke Romano, Owen Franks, Codie Taylor, Wyatt Crockett. Reserves: Ben Funnell, Tim Perry, Michael Alaalatoa, Mitchell Dunshea, Pete Samu, Bryn Hall, Marty McKenzie, Manasa Mataele.