The planned renovation to Hayward Field has been delayed again, according to multiple sources.

The project now is expected to begin next summer -- two years after the start date on the original timeline.

Sources say the renovation is expected to take more than a year and not be complete until some point in 2020.

The stadium is expected to be closed during renovation, which sources say could force the 2019 Prefontaine Classic, the 2019 NCAA Outdoor Championships and the 2019 OSAA Track & Field Championships to relocate.

If the latest timeline holds, the Oregon Ducks would not have a home schedule in 2019, and probably be forced to practice elsewhere.

TrackTown USA president Vin Lananna said concern about the big meets in 2019 is premature.

"The timeline has not been finalized," Lananna said.

Lananna has been a prime mover behind staging big meets in Eugene such as the U.S. Olympic Trials in 2008, 2012 and 2016, and the World Junior Championships in 2014. He led the team that successfully bid for the 2021 World Outdoor Championships.

The renovation is necessary to bring the University of Oregon's iconic track stadium up to specifications for the world championships.

Eugene received the bid with the proviso the stadium be modernized and its capacity expanded to 30,000 permanent and temporary seats. Hayward Field's current listed capacity is 10,500.

Original plans called for construction crews to begin immediately after the conclusion of the 2016 U.S. Olympic Trials. The renovation was supposed to result in approximately 14,000 seats. At the time, the projected cost was $68 million.

The project has been delayed several times since, and blueprints for the renovated stadium altered. The current revision calls for approximately 10,000 permanent seats, sources say.

Nike executive Todd Van Horne reportedly spent time in Europe this summer examining similar-sized track stadiums.

It's unclear whether Nike will have any direct involvement with the project. But Nike co-founder Phil Knight, a former UO mid-distance runner, is expected to donate to it.

Under the project's original timeline, construction was to stop temporarily in 2017 to allow Hayward Field to stage the Prefontaine Classic, the state high school championships and the NCAA Championships, and then resume.

Sources say they believe there will not be a similar pause in 2019 on the new timeline.

The Prefontaine Classic, the only U.S. meet on the elite Diamond League track circuit, is known to be looking at other sites for the 2019 meet.

Meet officials are said to be investigating in-state locations such as Lane Community College, the Whyte Track & Field Center at Oregon State, Mt. Hood Community College and Griswold Stadium at Lewis & Clark College. Moving the meet out of state also is a possibility.

No matter where it is held, the 2019 Pre Classic is expected to move from late May to late July or early August because of changes in the international schedule.

The NCAA Division I Outdoor Championships have been awarded to Eugene through 2021. The NCAA website lists Eugene as the 2019 site.

Brad Garrett, OSAA assistant executive director, said Oregon high school officials are aware there could be possible conflicts between the state meet and the renovation at some point.

But, Garrett said, "we have not been informed by the University of Oregon that Hayward Field is not a viable site for us in 2019."

-- Ken Goe

kgoe@oregonian.com | @KenGoe