Here's more detail in the story:
From the Herald:
“When the San Francisco 49ers and Green Bay Packers visited [UM] ahead of the NFL Championship Game for a site visit,’’ the NFL.com story said, there was one problem: Both potential Super Bowl LIV participants deemed the practice surface unsuitable, sources say...
“The field was deemed unsafe in accordance with NFL standards,’’ the report said, with NFL officials agreeing “with the initial sentiments” after testing.
49ers officials, along with Miami and the NFL “and other interested parties,” including “local officials,” eventually “struck a deal to replace the field under certain agreed-upon circumstances, meaning San Francisco didn’t need to relocated its entire operation elsewhere...
“At this point, local officials got involved and the resolution was reached: The field would be replaced and if The U didn’t like it later, they could have it replaced to their liking.’’any field changes were “at the 49ers expense’’