DETROIT -- Cubs outfielder Reed Johnson, sidelined with lower back spasms, is expected to be placed on the 15-day disabled list Thursday and Ryan Freel called up from Triple-A Iowa.

Johnson, who was batting .268 with four home runs and 16 RBIs, has not played since Saturday.

"We can't continue to play short," Cubs manager Lou Piniella said Wednesday.

Johnson's injury comes at an inopportune time. He had four home runs and 10 RBIs in his last 18 games, and he provides some energy. Johnson also had contributed to the Cubs' recent winning streak.

"Every time it seems like we have a little something going here, we suffer a little setback -- [Angel] Guzman in the bullpen and now Reed Johnson," Piniella said. "We've got to fight through it, what can I say? We need to get [Aramis] Ramirez back in the lineup and then we can set up the lineup the way we want, and I think we'll get a lot more consistent offensively."

Ramirez is getting closer. Out since May 9 with a dislocated left shoulder, the third baseman had a good workout Wednesday at Comerica Park. He'll take Thursday off, then start taking batting practice Friday in Chicago. Once Ramirez passes that test, he'll be ready for a Minor League rehab assignment.

"Depending on how he feels, the next thing will be to go out and get some at-bats," Piniella said.

Freel had been on the disabled list since May 28 because of a strained left hamstring. In seven games with Triple-A Iowa, Freel was batting .417 (10-for-24) with four doubles and four RBIs.