Doolittle, on the DL with a right intercostal strain, did some "sock throws" on Monday and could play catch soon. Asked whether Doolittle could return when he is first eligible on Sept. 8, Melvin responded: "I wouldn't rule anything out."
Jaso went on the seven-day concussion DL on Aug. 24, and he hit in the cage on Monday.
And Crisp, who aggravated his neck issue crashing into the wall Friday in Anaheim, took swings right-handed on Monday. He will receive trigger point injections on Tuesday, which he has done several times this season to alleviate the pain in his neck.
"We have some key guys that are out, that's no secret," said Melvin. "Those are guys that are important to us and we hope to get the rest of them back sooner than later."
Aaron Leibowitz is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.