Vatanen, 25, was a late scratch because of an upper-body injury prior to a 3-2 victory against the Flames in Game 2 at Honda Center on Saturday. The Ducks lead the best-of-7 series 2-0.
"There was a question mark whether his injury was responding to the treatment, and obviously it did not, to the point where he wasn't comfortable going out there," Caryle said. "We leave it up to the player to make the decision if he can play or not, and he said he wasn't 100 percent to compete."
Vatanen led Anaheim defensemen in scoring the previous two seasons, including an NHL career-high 12 goals in 2014-15. He had an NHL career-best 38 points (nine goals, 29 assissts) in 71 games last season but dipped to 24 (three goals, 21 assists) in 71 games this season.
The Ducks' other injured defenseman, Cam Fowler, is expected to begin slide-board work in the gym while the Ducks are in Calgary, Carlyle said. Fowler injured his knee in the final regular-season game against the Flames, on April 4, and was given a recovery timeline of 2-6 weeks.
"That will indicate whether he'll step on the ice and how soon he gets there, once he's able to do [slide-board workouts] pain free and movement free," Carlyle said.
With Vatanen and Fowler out for Game 2, the Ducks had four defensemen in the lineup -- Korbinian Holzer, Brandon Montour, Shea Theodore and Josh Manson -- with a combined 10 games of Stanley Cup Playoff experience entering the game.
"We thought we were going to have to use nine defensemen through the course of the playoff season and we're at eight right now," Carlyle said. "That's great for our younger kids that are getting the exposure and the experience of playoff hockey, and it should only bode well for their futures, to get a taste of what playoff hockey is like, but I don't see them intimidated by it."
