The news came shortly after Johnson threw a flat-ground side session at the Cubs' complex at HoHoKam Park. Johnson has been working his way back from surgery to repair a herniated disk in his back in August.
Johnson mixed in a few sliders and changeups during his side session, which was designed more to "get the kinks out" than as a serious physical test, and manager Bob Melvin said Johnson has proven himself ready for game action.
"This is exactly where we kind of had it mapped out to," Melvin said. "We're right on schedule."
Johnson, 44, was 4-3 with a 3.81 ERA in 10 starts last season, his first since returning to the Diamondbacks.
Melvin said he doesn't know how long Johnson's outing will be Monday, but the club is looking forward to getting Johnson into game action.
"Sure, I think everybody is, him more than anybody else," Melvin said.
Mark Thoma is a contributor to MLB.com. This story was not subject to the approval of Major League Baseball or its clubs.