KANSAS CITY, Mo. (WDAF) — The San Francisco 49ers are unhappy with their Super Bowl LVIII practice facility, according to multiple reports.

The 49ers are practicing at the University of Nevada-Las Vegas facility, which had sod placed on top of two artificial surface fields last week.

The NFL ordinarily requires Super Bowl practice fields to meet certain standards in December, ESPN’s Adam Schefter reported.

Sources told Schefter that the NFL hardness score for fields averages 78, with no field being less than 70. The 49ers’ field is considered in the 50s.

Representatives for the 49ers examined the UNLV fields late in the week and compared the practice field to a “sponge” when reporting back to team officials, according to NBC Sports Bay Area.

The Kansas City Chiefs are practicing at the Las Vegas Raiders facility in nearby Henderson, Nevada, as the home team.

The Athletic’s Matt Barrows reported that the Chiefs have been unwilling to change their practice schedule for the Niners to also practice at the Raiders facility, and the NFL will not force Kansas City to change their schedule.

Barrows also reported that San Francisco was so dissatisfied that they considered flying back to Santa Clara to practice there before Monday night’s media event.

NFL Commissioner Roger Goodell said the field has been inspected and approved by the league.

“We’ve had 23 experts out there. We had the union out there. All of them think it’s a very playable surface,” Goodell said at his Super Bowl news conference Monday.

The league, along with the NFL Players Association, inspects the playing surfaces before every Super Bowl and approved each facility for use this week.

“It’s softer than what they practiced on, but that happens. It’s well within all of our testing standards,” Goodell said. “It’s something we think all of our experts, as well as neutral field inspectors, have all said unanimously, that it’s a playable field.”