Plans to hold a public training camp practice for up to 20,000 fans at Levi's Stadium on Sunday were scrapped due to poor playing conditions on the grass field, the San Francisco 49ers announced Thursday night.

Practice will be moved to the adjacent practice facility, closed to the public and will not be rescheduled.

The team had promoted a free random drawing, first for 10,000 fans before upping the number to 20,000 last week.

"We extend our sincere apologies to those fans who were scheduled to attend Sunday's practice," Jim Mercurio, vice president of stadium operations and general manager of Levi's Stadium, said in a statement. "After a thorough inspection earlier today, our grounds crew determined that the field would not be ready by Sunday. Therefore, the recommendation was made to relocate practice. We remain confident that our turf management program will provide a playing surface that meets the team's standards, as we enter the 2015 NFL season."

The 49ers, who are expected to replace the Levi's Stadium sod six or seven times this year, canceled a public practice due to poor and unsafe field conditions. Kyle Terada/USA TODAY Sports

The Niners, under new coach Jim Tomsula, initially planned to hold their first eight training camp practices at Levi's Stadium, but were forced to move operations next door after two practices and returned for a fan event practice Wednesday night.

But, as it did in the first two practices, the sod gave way throughout the field, with large divots flying up when players planted their feet and cut. Rookie running back Mike Davis took a particularly nasty spill trying to change his direction Wednesday night and limped off the field before returning to practice.

Grass problems have been an issue since the $1.3 billion stadium opened last year. Former coach Jim Harbaugh abruptly ended a public practice last year and marched his team off the field when the grass became an issue.

The field was replaced at least three times last year.

In the past few weeks, the field has played host to an international soccer match between Manchester United and Barcelona, and a high school football all-star game immediately before the Niners' first practice.

A pair of Taylor Swift concerts are scheduled for Aug. 14 and 15, as well as a Luke Bryan concert on Aug. 29. The 49ers have preseason games against the Dallas Cowboys on Aug. 23 and against the San Diego Chargers on Aug. 29.

The field is scheduled to be replaced six or seven times this year, including before the regular-season opener against the Minnesota Vikings on Monday Night Football on Sept. 14.

Super Bowl 50 will be held on a new field at Levi's Stadium on Feb. 7.