Source: 49ers concerned about Vegas practice field ahead of Super Bowl

LAS VEGAS — The 49ers arrived in the Super Bowl host city on Sunday evening without a firm practice field or a firm plan for where they will hold their workouts during the week. The 49ers were assigned to practice on the UNLV campus, where last week natural grass was laid on top of two artificial-surface fields. However, the condition of the fields has generated safety concerns with the surface lacking necessary firmness, league sources told NBC Sports Bay Area. When 49ers representatives examined the UNLV fields late in the week, they likened the practice field to a "sponge" when reporting back to team officials. One source said scores are assigned to fields and a standard NFL field is required to be in the 70 to 80 range. The 49ers' practice field scored 48 to 50. One source said there was no base put down between the artificial surface and the layer of sod. There are also noticeable seams in the field, where the sections of sods connect, according to a source. The 49ers are likely upset the fields were not installed sooner in order to allow time to make the necessary corrections. The team was scheduled to travel 20 miles from their team hotel at Lake Las Vegas Resort to UNLV...