Hughes suffered the injury reaching for a throw while covering first base during a fielding drill Monday. Cashman said Hughes would be treated with anti-inflammatory medication and would not do anything for another four days or so before beginning some light physical therapy.
"Hopefully it's nothing major," Cashman said. "The doctor clearly isn't aggressively treating it, and that's a good sign, but there's no guarantees until we get through the two-week process and we see where he's at.
"I'm not going to BS you and say we're not [concerned]. We won't be out of the woods until we see all that stuff. It's a question mark until we can all forget about that it ever happened."
According to Hughes, the injury is between his T5 and T6 vertebrae, approximately in the middle of his back between the shoulder blades. He said that although the injury is not directly affecting his pitching arm, he feels discomfort in the right side of his back.
"The first day was rough getting out of bed and stuff like that," he said. "Now I'm moving around a lot better. I don't feel it just standing here or anything. That part's encouraging, and I feel like in three or four days, once I go through these meds, that I'm going to feel that much better."
Hughes, who went 16-13 with a 4.23 ERA, came to camp this year penciled in as the Yankees' No. 4 starter behind CC Sabathia, Hiroki Kuroda and Andy Pettitte. The Yankees felt he came to camp in better shape than in previous years and was ahead of schedule at the time of the injury, which could help speed his recovery.
"Hopefully this two-week timeout won't be that big a deal given that he worked so hard this winter," Cashman said. "I just want it to go away."