Jeter, 38, suffered a broken bone in his left ankle during last year's playoffs and underwent surgery. He has been undergoing rehabilitation treatment at the Yankees' facilities in Florida but an examination this week indicated a small crack in the same ankle.
Cashman said the Yankees are "looking at sometime after the All-Star break" for Jeter's possible return.
"He is obviously the toughest (player) we've ever had," Cashman said Thursday. "You know what Derek Jeter continues to have issues that don't go away, you know that means more than just your typical something."
Last season he hit .316 with 15 home runs and 58 runs batted in. Jeter has played 18 seasons -- all with the Yankees -- hitting .313 amassing 3,304 hits, 255 home runs and 1,254 RBI. The 3,304 hits are 10th most all-time.
He was Rookie of the Year in 1996 and is a 13-time All-Star selection.