EUGENE (AP) — The University of Oregon’s plan to build a new basketball arena moved a giant step forward Monday when Nike co-founder Phil Knight, and his wife, Penny, pledged $100 million to the university, the largest philanthropic gift in school history.

The money is not targeted specifically for an arena, university officials said. Rather, it will create the Oregon Athletics Legacy Fund, which will help support all athletic programs.

But indirectly, officials said, the donation will boost the university’s effort to replace aging McArthur Court with a new arena near the eastern edge of campus.

“This extraordinary gift will set Oregon athletics on a course toward certain self sufficiency and create the flexibility and financial capacity for the university to move forward with the new athletic arena,’’ Athletic Director Pat Kilkenny said. “Now we can roll up our sleeves and get to work on making the arena a reality.’’

The university last year estimated it would take more than $200 million to pay for the arena once land costs are figured in. Fundraising for the project has been one of the top priorities for Kilkenny since he got the job earlier this year.

University spokesman Phil Weiler, though emphasizing that the gift from the Knights is separate from arena fundraising, said the UO is fully committed to building the arena and hopes to have announcement on the project in the near future.

The $100 million gift is the lead contribution toward a $150 million goal for the legacy fund, the university said.

Phil Knight ran track for the Ducks and graduated in 1959 with a bachelor’s degree in accounting. He and wife have been longtime supporters of the university and are now the largest donors in school history.

Prior gifts have included money for the School of Law, the UO Libraries, more than 15 endowed faculty positions, and a number of other academic and athletic gifts.

“They have demonstrated a deep commitment to fostering both athletic as well as academic excellence on the Oregon campus,’’ UO President Dave Frohnmayer said in a statement. “This contribution reflects a continuing strong dedication to higher education and our students. We are deeply moved by their unprecedented generosity.’’