HENDERSON, Nev. >> JC Tretter, president of the NFL Players Association, said today that plastic was supposed to be placed on top of UNLV’s practice fields but was never installed.

“I don’t know how that doesn’t happen,” Tretter said.

The NFL placed natural grass on top of the Rebels’ field turf, and San Francisco 49ers coach Kyle Shanahan complained it was too soft. But Shanahan said the team will practice there all week instead of trying to find another field and another time for practice.

“This is the best choice we’ve got,” he said after today’s practice.

“We’re here. We’re practicing on it. Everyone has their preferences. We wish things were better, but we’ll deal with it how it is.

The 49ers are practicing at UNLV this week for Sunday’s Super Bowl against the Kansas City Chiefs. Kansas City is working out at the Las Vegas Raiders’ facility.

NFL Commissioner Roger Goodell said Monday that the playing surface at UNLV met the necessary standards and the union signed off on it as did 23 experts.

“It’s softer than what they practiced on, but that happens,” Goodell said.

Tretter said the standards needed to be higher.

“Playable is not the same thing as high quality,” Tretter said. “So, we can’t kinda talk out of both sides of our mouth on this.”

49ers players, however, raved about the other facilities at UNLV.

“I’m shocked because they’re in the Mountain West,” said safety Tashaun Gipson, who played in that conference at Wyoming. “I’m shocked the locker room is that nice. We’ve got to do better at Wyoming. The fields are the fields, but the weight room and everything is pretty decent.”

Cornerback Deommodore Lenoir played at Oregon, known for having excellent facilities.

“UNLV, I love their locker room,” Lenoir said. “It reminds me of Oregon’s. The whole setup was exactly how ours was. The facilities are just like Oregon’s, too.”

BIENIEMY VISITS OLD TEAM

Former Kansas City offensive coordinator Eric Bieniemy talked with his former players and even attended meetings before the Chiefs played the Baltimore Ravens in the AFC championship game.

“It’s always great to have EB in the building,” quarterback Patrick Mahomes said. “The energy that he brings and the mentality that he brings, you can feel.”

Bieniemy was the Chiefs’ offensive coordinator for five seasons, but left last year for the same position at Washington. After multiple failed attempts to land a head coaching job, he wanted to show he could be an effective offensive coordinator when no longer under the shadow of Mahomes and coach Andy Reid.

But Commanders coach Ron Rivera was on the hot seat entering this season, and in fact was fired along with his staff on Jan. 8.

“His coaching future is great,” Reid said of Bieniemy. “I’m obviously a big fan of his, and I know the things he can do.”

LIKE FATHER, LIKE SON

Kyle Shanahan has been around the NFL for almost as long as he can remember. He was just 4 when his father, Mike, got his first job in the NFL as an assistant in Denver, and the younger Shanahan followed along after that, frequently attending practices and games as his dad worked for the Broncos, Raiders and 49ers.

Kyle Shanahan takes pride in being the last person to hold the wires for a head coach in the Super Bowl in the 1997 season with the NFL going to wireless headsets the following season.

But it was all the lessons he learned watching his dad coach that help him most today.

“You don’t realize how much it helps you until you get in it,” Kyle Shanahan said. “You just realize that a lot of the stuff you’ve been around and it makes it a little easier. Not only was I a son of a coach, but my dad’s the best coach I’ve ever been around. To be around that good of one, I think also was a huge advantage for me.”

PEELING BACK THE CURTAIN

Chiefs president Mark Donovan gave a few local reporters today the first glimpse behind the scenes of what it took to host pop superstar Taylor Swift at games this season, beginning with the “week of” warning he got from tight end Travis Kelce.

“Very first conversation I had with Travis,” Donovan recalled, “I told him, ‘The one thing you can count on from us is we’re going to be very respectful. We’re going to respect your relationship first and foremost. As much as this is an amazing opportunity, we are not going to do that stuff. I think it’s important for you to appreciate what this is.’”

That meant the Chiefs never played a Taylor Swift song in Arrowhead Stadium all season. Never showed her on the video boards unless they were showing all the celebrities in attendance. They certainly didn’t ask her to sing the national anthem.

“The first time we had her was, as you can imagine, full of meetings with security, police, how we’re getting her in, what we are going to hide, what we are not going to hide,” Donovan said. “How do you move a superstar like that, and do it safely? Then we did it, and typical Travis, we had this great protocol for leaving, exactly how we were going to do it, and he grabs her in a convertible and takes off. I texted him later, ‘That exit was epic.’”

THUNEY HOLDING OUT HOPE

Chiefs left guard Joe Thuney, who suffered a pectoral injury against the Ravens, hasn’t given up playing Sunday — even if the odds are against him.

“Trying to do everything I can to be healthy enough to play,” Thuney said. “We’ll see how it goes.”

If he can’t play, fifth-year pro Nick Allegretti likely will start.

“I prepare like I’m starting every week,” Allegretti said. “I prepare like I’m starting for all three positions. Just making sure I have the run game formations down, the motions down. I’ve built really good chemistry with (center) Creed (Humphrey and (tackle) Donovan (Smith) the last few weeks, so that’s been awesome.”