49ers displeased with Super Bowl practice field, sources say

Field conditions at the San Francisco 49ers' practice facility at UNLV have drawn widespread disapproval from various members of their organization, sources told ESPN's Adam Schefter.

The NFL installed a turf field on top of the turf and began laying it last week, while the NFL usually requires Super Bowl practice fields to meet certain standards in December, sources told Schefter.

The NFL's hardness score for fields averages 78, with no field below 70. The 49ers' field is considered in the 50s, sources told Schefter.

The 49ers will hold their first on-field practice later Monday.

The Kansas City Chiefs are practicing this week at the Las Vegas Raiders practice facility.

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

The playing surface was a scenario in Glendale, Ariz., for last year's Super Bowl, particularly the slick track that led to the Chiefs and Philadelphia Eagles struggling to find safe footing throughout Match.

CBS Sports first reported the 49ers' dissatisfaction with their practice facility.

Field Level Media contributed to this report.