Thome, who had an epidural in Los Angeles on Thursday, said he was told by the doctors to not do any baseball activity for 30 days and he will be reassessed after that. The 41-year-old, acquired in a July 1 trade with Philadelphia, said the injury news was disappointing, but tried to remain optimistic.
"It is because we're in a pennant race," Thome said. "You come over, you want to help. These guys have had a great year and I want to be a part of that. And it's still not over.
"The big thing is, as I said, you've got to have a good mental outlook on things. We have the month of September. Will it be all of September? I don't know. Again, it's hard to pinpoint a date, a month, a time and all of that."
Thome has hit .261 with two homers and six RBIs in 18 games since joining Baltimore, serving as the team's primary DH. He last played on July 27, with Chris Davis assuming the bulk of DH duties in Thome's absence.
"We feel like we're going to have two real good September additions, not from our Minor Leagues, in Jim Thome and Jason Hammel," manager Buck Showalter said. "We hope, knock on wood."
Asked if this DL trip had changed his mind about the future, Thome was hesitant to definitively say whether he would play in 2013.
"But you know what, this maybe changes my thinking a little bit," Thome said. "Maybe I do want to play a little bit longer. Again, I am trying to get back. I am not worried about next year. I think I'm trying to focus on this year, try to do the best to get back as quick as I can and to help us maybe accomplish and reach some special things here toward the end of September, through October. We'll come to that once that time frame hits."