"He threw a bullpen [session] a couple days ago," manager Brad Ausmus said. "No negative side effects."
Lobstein has been on the 15-day disabled list since May 24 with left shoulder soreness, a problem that he pitched through for a few weeks before that. What was hoped to be a quick rest and recovery has become more of a summer-long struggle, with Lobstein doing most of his throwing off flat ground while progressing slowly.
Lobstein became a presence in April, filling in for injured Justin Verlander, and he went 3-5 with a 4.34 ERA in eight starts. The ERA took a hit in his final three starts while he was pitching through the shoulder soreness.
Verlander is back, but with Alfredo Simon and Shane Greene struggling to pitch deep into games to give the Tigers a chance, Lobstein's loss actually looms larger. Even as an insurance option or an extra lefty reliever, Lobstein could play a role down the stretch.
"It would be nice to have his arm," Ausmus said. "He pitched pretty well for us early in the year. He was pitching hurt and he gave us an opportunity to win games, kept us in games."
Jason Beck is a reporter for MLB.com. Read Beck's Blog, follow him on Twitter @beckjason and listen to his podcast. This story was not subject to the approval of Major League Baseball or its clubs.