Venable was acquired to give the Rangers depth in the outfield while Hamilton deals with his knee issue.
Hamilton was out of the lineup on Wednesday for the fourth straight game because of the knee. He had a cortisone shot last week and admitted that it didn't provide any relief, and his knee felt worse after the Rangers flew into Detroit on Wednesday night.
"If a guy can't go by the fifth day and it doesn't look like it's going to be imminent, [the DL] is probably necessary," Rangers manager Jeff Banister said Thursday. "We didn't want to continue to play short."
It didn't appear that trying to play through the pain was an option.
"If I could play through it, I would be out there right now," Hamilton said on Wednesday. "If I went out there right now, we would be back where we were four days ago: swollen or worse."
Hamilton had an MRI on Friday that showed no structural damage to the knee. But the pain is still there.
"It's difficult to put the finger on what it is," Hamilton said. "Structurally, the ACL and all that stuff is OK. It feels pretty good when I'm getting treatment, but when I stand up and put weight on it, it locks up again. It's just weird."
Hamilton, who was acquired from the Angels on April 27, spent the first two months of the season on the DL while recovering from offseason shoulder surgery. The Rangers activated him May 25, but he missed almost all of June with a strained left hamstring.
"If the hamstring doesn't happen, it's a different ballgame," Hamilton said. "But it happened, so since then there has been one thing after another."
There is a possibility Hamilton may need surgery after the season. It would mark his third career operation on his left knee.
"I've got to talk to the doc about that," Hamilton said. "We're trying to figure out what's next."
T.R. Sullivan is a reporter for MLB.com. Read his blog, Postcards from Elysian Fields, follow him on Twitter @Sullivan_Ranger and listen to his podcast.
Alejandro Zúñiga, an associate reporter, contributed to this report. This story was not subject to the approval of Major League Baseball or its clubs.