Illinois Lt. Gov. Sheila Simon (D) said Wednesday that she will not seek reelection on a ticket with Gov. Pat Quinn (D), the latest blow to the already embattled governor.

"I believe I've been effective as lieutenant governor, and I think I can be more effective in other office, and I look forward to that," Simon said.

Simon, the daughter of former senator Paul Simon (D-Ill.), is thought to be a potential contender for state comptroller or state attorney general, provided current Attorney General Lisa Madigan (D) challenges Quinn for the governorship.

That remains an open question, but Quinn is expected to get major primary opposition -- either from Madigan, former White House chief of staff Bill Daley or both.

A poll conducted by Southern Illinois University this week showed Madigan leading that field of three candidates.

Quinn has just a 33 percent approval rating, with 51 percent disapproving, and he narrowly survived his 2010 primary after ascending to governor following Rod Blagojevich's resignation.