Allison Mack in Smallville by Michael Courtney/The CW Allison Mack in Smallville by Michael Courtney/The CW

It looks like Smallville's about to take another, potentially lethal, hit.

Just a week after it was announced that Michael Rosenbaum would not be returning full time as Lex next season, sources confirm to me exclusively that Allison Mack, arguably Smallville's most popular heroine, may be the next to go.

This marks quite a turnaround from a few months ago, when I deemed Mack a lock to come back next season. And I wasn't the only one. Although a deal wasn't signed at the time, Smallville insiders tell me that all indications were that the actress was on board for Season 8.

But then Rosenbaum terndered his resignation and everything fell apart.

"Allison's camp used Michael leaving as leverage in the negotiations with [Warner Bros.]," says one Smallville source, who adds that Kristin Kreuk's decision to only return for a handful of episodes as Lana only strengthened Mack's bargaining position. "They need Chloe now more than ever - and Allison's people know it." (Mack's reps declined to comment for this story.)

But will the studio suits budge? In this climate, with ratings down by double digits and belt-tightening going on everywhere, no one is optimistic. However, everyone pretty much agrees about one thing: Smallville can't afford to lose Mack right now. "If Allison leaves, they've essentially got Lois and Clark left," notes one insider. "And that show's been done before."

So, what do you think? Should Warner Bros. man up and give Mack what she's probably been worth all along? Or are you OK with Smallville turning into Lois & Clark: The Early Years? Sound off below!