Lohse strained his right forearm flexor on Wednesday when he threw to first after fielding a bunt by the Reds' Johnny Cueto. He originally suffered the injury on May 23 when he was hit by a pitch, but aggravated the injury on Wednesday in his first appearance since then.
It's Lohse's first trip to the DL in his nine-year career.
"It was a good run, and you hate to go out on something like that," Lohse said. "But I need the rest and we need to make sure it gets back healthier than it was before.
"Every start, it seems that I've been frustrated with some little injury, and none of them are throwing related, really. I'm going to hate having to sit here and watch and not be able to help the guys out."
Lohse is 4-4 with a 3.99 ERA for the Cardinals, who entered Friday night's game against the Rockies tied for first place in the National League Central with the Milwaukee Brewers.
With infielder Joe Thurston expected to leave the club any day to be with his wife for the birth of their first child, the team gave the open roster spot to infielder Greene. The right-handed-hitting Greene was with the Cardinals for a short time earlier this season and hit .263 in 38 at-bats.
Greene was in the lineup for Friday night's series opener against Colorado, batting ninth and playing shortstop.
B.J. Rains is an associate reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.