Johnson, who has chronic back problems resulting from 2007 disk surgery, said he was making steady progress until a flareup after resuming running on a treadmill Monday.
"That set me back a few days," said Johnson. "I aggravated it a little bit, not anywhere close to where it was two weeks ago. I didn't have to start completely over, but I'm not where I thought I would be. Running is always the last thing I have to do to get ready to come back. It's frustrating to get this close and all of a sudden have a setback."
Johnson is eligible to return Saturday and was planning to. With Manny Ramirez expected to be disabled for three weeks, the Dodgers were hoping for a quick return from Johnson. They are shorthanded enough for right-handed-hitting outfielders that they've been using utility infielder Jamey Carroll there.
The Dodgers' bench is further limited because of the uncertain state of the bullpen, management choosing to carry 13 pitchers and a bench of only four position players.
"Do I want 13? No," said manager Joe Torre. "Do I need 13? Yeah. It's safer to do it this way. By the road trip we can switch back."
Johnson said he is hoping to continue getting treatment with the club when it visits San Diego, then he hopes to go out on a brief Minor League rehab assignment before returning.