Jeter, who is nursing a sore, surgically repaired left ankle, hasn't missed a Yankee Stadium opener since 2001.
Cashman said the New York captain will probably be on the shelf when the Yankees host Detroit April 6.
The team begins the season April 1 on the road against Boston.
Eduardo Nunez is set to replace Jeter as the team's everyday shortstop while the 38-year-old veteran stays behind in Florida to work on the ankle.
Jeter fractured the ankle during Game 1 of last year's American League Championship series against the Tigers.