Peter Sciretta, for /Film:
The Han Solo injury happened mid-way through production and involved a large segment of the Millennium Falcon which came loose and landing and breaking Ford’s leg. When the accident happened, Abrams expected to have to rewrite the rest of the script so that Han Solo spent his time sitting in chairs. But that ended up not being the case
Abrams told the magazine that the injury was actually the “greatest gift to the movie”
The break in production gave Abrams and writer Lawrence Kasdan time to rewrite and rework upcoming scenes, as well as reshoot some footage that they weren’t happy with, and also giving the other actors extra time to rehearse. Writer Lawrence Kasdan adds that when Ford returned to the production “a strange kind of thing” happened where the actor “lit up the whole place.”
Clearly, Harrison Ford is the man.