Greg Grunberg "saved" Matthew Fox's character.

[gangstaduck]

In the original draft, Dr Jack died in the first episode. "I remember reading it and thinking, 'No way'," Grunberg says. "This is the character everybody connects with and everybody loves. You can't have him die, so they rewrote it."

Damn it Grunberg! We could have been rid of him then!

From here.