But the Cats have only upgraded ruckman Mark Blicavs from their rookie list at this stage.
Christensen had back surgery during the off-season and is expected to return in rounds eight to 10.
Vardy suffered a season-ending knee injury at training last month.
He had surgery a week ago, is set to travel to Europe for a holiday in June and July, and won't return to the field until 2015.
Menzel is on the comeback trail after undergoing his fourth knee reconstruction last year. He is progressing well and should be back on the park during the second half of the season.
Blicavs was temporarily promoted to the club's senior list last year, and he went on to enjoy a brilliant season, playing 22 games, including three finals.
He was returned to the rookie list at the end of last season because the club needed to promote George Burbury and Josh Walker, who had both spent three years as rookies.
Geelong will have two vacant spots on its senior list until Christensen and Menzel return.
Third-year rookie Jackson Sheringham is considered a strong chance to take one of the spots if his VFL form is strong in the coming weeks.