Some 49ers staffers "are not pleased with the practice field" at UNLV, where the NFL designated the team to practice during Super Bowl week, and at issue is "the firmness of the natural grass the NFL has laid over UNLV's artificial turf," according to sources. A 49ers advance group feels the grass is "too soft for the team to practice on, and the team has considered alternatives." Sources said that "this is not a health-and-safety issue as much as it's simply a preference issue." The 49ers' options include practicing on the field as scheduled or bringing in "new, firmer sod that would, in theory, be ready for practice this week." Sources said there also have been "discussions about the 49ers adjusting their schedule that would allow for them to practice at the Raiders' facilities when the Chiefs aren't there" (CBSSPORTS.com, 2/5).