Foundation Executive Director John Heubusch told the audience Tuesday at the Reagan presidential library in Simi Valley, Calif., that the former first lady wouldn't attend the speech "on doctor's orders," CBS News reported.
"She's fine but still nursing some broken ribs from a fall that several of you heard about weeks ago," Heubusch said.
A representative for the former first lady, 90, said she fell in March, CNN reported.
"Mrs. Reagan has been recovering slowly and has been adding a few appointments back on to her schedule, but was advised by her doctor today not to try and attend large events too far from home just yet," Reagan spokeswoman Joanne Drake said. "She personally invited Congressman Ryan and really wanted to be here, but sent her apologies to him earlier today."