Lohse has not begun throwing since being put on the shelf, but he said after the Cardinals' 4-3 loss to the Marlins on Tuesday that he hasn't been given a timetable as to when he can return to the mound.
Earlier, though, The St. Louis Post-Dispatch -- citing club sources -- said Lohse is expected to miss four weeks and could possibly be out through the All-Star break.
"I think that's too long, but anything is possible," Lohse said. "It's a strain and there's a lot of swelling in the muscle. But we're just working every day trying to get [the swelling] out of there."
"Slow right now," is how Lohse described his recovery. And though he said he hopes to begin lightly tossing within the next three or four days, he knows he's going to have to give the healing process time.
"Just taking it day-by-day," Lohse said. "You have to let it heal, and there's no real timetable as to how fast anybody can heal. All I know is I haven't thrown a ball ever since I came out of that game [last Wednesday]. Hopefully soon, in the next three or four days, I'll be able to lightly toss, but I can't really say. It's not better yet, so I don't know when it will be."
The first DL stint in Lohse's career is retroactive to Thursday.
The 30-year-old right-hander originally suffered the injury to his forearm on May 23, when he was hit by a pitch from Royals reliever Ron Mahay. Lohse then reaggravated it his next time on the mound -- last Wednesday -- when throwing to first base after fielding a bunt by Reds starter Johnny Cueto.
In his ninth Major League season -- and second with the Cardinals -- Lohse is 4-4 with a 3.99 ERA in 10 starts.
"He's getting the swelling, all that pain out of there," Cardinals manager Tony La Russa said prior to Tuesday's game. "I know he is feeling improved. He's getting treatment, so as soon as he can, he'll start throwing. But we're not giving any timetable for him coming back."
To fill Lohse's spot in the rotation, the Cardinals will continue to go with Brad Thompson -- a long reliever and spot starter his previous four years.
Thompson is 0-2 with a 4.50 ERA in 11 games (two starts) this season. In those two starts, the 27-year-old right-hander has given up five runs in 9 1/3 innings.
For his career, Thompson sports a 4.26 ERA and has started 26 games, including 17 in 2007.
"Take it one start at a time, but he's the best guy we have to do it right now," pitching coach Dave Duncan said. "As long as we feel like he is, we'll give him starts at that spot.
"He's done a good job for us overall. You can't let your expectations get too high because we know what Brad's true strengths to our club is -- that's long relief and spot starting just like he's doing right now."
Alden Gonzalez is a reporter for MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.