Kesler was injured against Winnipeg on Wednesday and returned to Vancouver while the team continued its road trip.
"Nothing we can do about that, upside is that it gives others an opportunity," Tortorella said at the team's morning skate prior to its game against the Washington Capitals.
It's a big blow to the struggling Canucks, who are in a fight for a playoff spot in the Western Conference.
"It's a huge game for us," forward Alex Burrows said of Friday's contest. "We need these points. I feel confident and will hopefully contribute again."
Burrows scored twice in Vancouver's 3-2 win over the Jets, a crucial victory for the Canucks after they blew a 4-0 third-period lead against the Islanders on Monday.
Heading into Friday's games, the 30-28-10 Canucks were four points behind Dallas for the final Western Conference wild-card spot.
Kesler has 22 goals and 18 assists this season.