"After doing two physically demanding films in a row, Tobey has experienced mild discomfort in his back, which is in the final stages of healing," Maguire's spokeswoman said in a statement. "With an April 12 start date around the corner, everyone involved wants to be certain he is able to do the intense stunts." Maguire wrapped "Spider-Man" in April 2001. Eighteen months later, he began production Oct. 15 on "Seabiscuit" in the role of racehorse jockey Red Pollard. The four-month shoot wrapped Feb. 18.

If Maguire exits, it would come only a month after his reps renegotiated a career-best $17 million payday for the actor. Maguire earned $4 million for "Spider-Man".  Waiting in the wings is Jake Gyllenhaal, star of "Moonlight Mile," "The Good Girl" and 20th Century Fox's own summer 2004 tentpole, "The Day After Tomorrow." Before Maguire was fitted for the red and blue suit, Gyllenhaal was on the short list of "Spider-Man" candidates. He can seem only more attractive now that he's also dating Dunst.