Rasmus has been mired in a 3-for-66 slump since July 2 and told reporters a few weeks ago he has been dealing with cholesteatoma, a growth of skin cells occurring behind the eardrum that causes damage. The Astros specified the injury as a cyst on Sunday.
The 29-year-old said he would eventually have to have surgery, though it's not known if he will undergo that while on the DL.
"That's certainly on a personal level for him, so I don't want to speculate or anything like that," Hinch said.
Hinch, who has seen infielder Luis Valbuena (right hamstring), pitcher Lance McCullers (right elbow sprain) and pitcher Luke Gregerson (left oblique) go on the DL in the past week, said his team will again be short-handed Sunday, with infielder Tyler White (knee) and outfielder Carlos Gomez (illness) also unavailable.
Kemp, ranked by MLBPipeline.com as the Astros' No. 16 prospect, flew through the night from Las Vegas to join the club in Houston, but he immediately had to be treated by a dentist upon his arrival in Houston for an issue that kept him out of the lineup Sunday for Fresno. He appeared in 22 games with the Astros earlier this year and hit .238 with three RBIs.
Brian McTaggart has covered the Astros since 2004, and for MLB.com since 2009. Follow @brianmctaggart on Twitter and listen to his podcast.
Jordan Ray is a reporter for MLB.com based in Houston.
This story was not subject to the approval of Major League Baseball or its clubs.