Fowler missed the first-round series against the Calgary Flames with a knee injury sustained in a regular-season game against the Flames on April 4. He was given a recovery time of 2-6 weeks.
Vatanen missed the final three games of the four-game sweep against Calgary with an upper-body injury.
Fowler led Anaheim defensemen during the regular season with 39 points (11 goals, 28 assists) in 80 games, and Vatanen was second with 24 points (three goals, 21 assists) in 71 games.
The Ducks could have as much as a week off between games after completing the sweep Wednesday. The Oilers lead the best-of-7 series 3-2. Game 6 is Saturday in San Jose.
Carlyle said the time off should benefit Fowler and Vatanen but wouldn't commit to either player being available for Game 1.
Ducks defenseman Shea Theodore was recalled from San Diego of the American Hockey League on April 2 and played back-to-back regular-season games against the Flames while Vatanen was out. Theodore remained in the lineup after Fowler was injured and had five points (two goals, three assists) against the Flames.
Carlyle said he expects defenseman Hampus Lindholm and forward Nate Thompson to be available for Game 1. Lindholm received treatment following Game 4 after getting bumped, and Thompson appeared shaken after taking a hit from Calgary defenseman Michael Stone at 13:48 of the third period.