A person associated with the university and knowledgeable about the matter, speaking on the condition of anonymity because the lawsuit had not been filed, told The Associated Press that it is an antitrust action.
The NCAA sanctions, which were agreed to by the university in July, included a $60 million fine that would be used nationally to finance child abuse prevention grants. The sanctions also included a four-year bowl game ban for the university's marquee football program, reduced football scholarships and the forfeiture of 112 wins but didn't include a suspension of the football program, the so-called death penalty.
The governor's office announced the news conference late Tuesday afternoon. His spokesman did not respond to repeated calls and emails seeking to confirm a Sports Illustrated story that cited anonymous sources saying a lawsuit was imminent.
Corbett's brief statement did not indicate whether his office coordinated its legal strategy with state Attorney General-elect Kathleen Kane, who is scheduled to be sworn in Jan. 15.
Kane, a Democrat, ran on a vow to investigate why it took state prosecutors nearly three years to chargeSandusky, an assistant under former football coach Joe Paterno. Corbett was the attorney general when that office took over the case in early 2009 and until he became governor in January 2011.
State and congressional lawmakers from Pennsylvania have objected to using the Penn State fine to finance activities in other states. Penn State has already made the first $12 million payment, and an NCAA task force is deciding how it should be spent.
The NCAA, which declined to comment Tuesday on the planned lawsuit, has said at least a quarter of the money would be spent in Pennsylvania.
Republican U.S. Rep. Charlie Dent called that an "unacceptable and unsatisfactory" response by the NCAA to a request from the state's U.S. House delegation that the whole $60 million be distributed to causes within the state.
Last week, state Sen. Jake Corman, a Republican whose district includes Penn State's main campus, said he plans to seek court action barring any of the first $12 million from being released to groups outside the state.
Sandusky, 68, was convicted in June on charges he sexually abused 10 boys, some on Penn State's campus. He's serving a 30- to 60-year state prison term.
Eight young men testified against him, describing a range of abuse they said went from grooming and manipulation to fondling, oral sex and anal rape when they were boys.
Sandusky did not testify at his trial but has maintained his innocence, acknowledging he showered with boys but insisting he never molested them.