Last night, at a screening for his new movie Trick 'r Treat, Baker confirmed that he would be returning to the franchise as Empire State University's Curt Connors — and perhaps the Lizard as well? When his Trick 'r Treat co-star Michael Dougherty teased that Baker's role in the fourth movie would consist of him hanging around in the background, to which Baker replied (perhaps jokingly) that he'd basically be doing just that. Dougherty lamented it would be a "cocktease for another year."
When asked about Spider-Man 4's possible villains, Sam Raimi mentioned that he's a fan of the Lizard. But it's possible that he'll hold off on the Lizard until the fifth and sixth films, which will reportedly follow a single storyline.
Dylan Baker Confirmed For Spider-Man 4 [UGO Movie Blog]