Scenes From Pre-Championship Sunday at Erin Hills

Darin Bevard, the USGA's director, championship agronomy, checks the green speed at Erin Hills with a Stimpmeter on Sunday. The official practice rounds for the 117th U.S. Open Championship begin on Monday, with the 72-hole competition commencing on Thursday. (USGA/Darren Carroll)

Rory McIlroy played Erin Hills for a second time on Sunday. The 2011 U.S. Open champion walked the venue on Friday and played the 11-year-old layout for the first time on Saturday. The four-time major champion had positive reviews for the course. (USGA/Darren Carroll)

Jordan Spieth, the 2015 U.S. Open champion, keeps an eye on his drive on the 12th hole. Because Sunday was not an official practice round, players were permitted to wear shorts. The 117th U.S. Open officially begins on Monday, with the 72-hole competition set to commence on Thursday. (USGA/Darren Carroll)

A caddie walks Erin Hills during Sunday's unofficial practice round. The 117th U.S. Open officially begins on Monday. (USGA/Darren Carroll)

Jason Day uses his phone to get a picture during his unofficial practice round on Sunday at Erin Hills. (USGA/Jeff Haynes)

Louis Oosthuizen and his caddie take in Erin Hills on Sunday. Players were permitted to wear shorts as this was an unofficial practice round. Championship week begins on Monday. (USGA/Jeff Haynes)

Oliver Bekker, one of the 15 qualifiers from the England sectional at Walton Heath Golf Club, watches his drive on the par-4 fifth hole. (USGA/Darren Carroll)

Winds is one of the key defenses for Erin Hills, an 11-year-old layout hosting its first U.S. Open this week. (USGA/Jeff Haynes)

This week, the grandstand at the par-3 ninth hole should have plenty of fans taking in the action from the 117th U.S. Open Championship at Erin Hills. (USGA/Jeff Haynes)

Amateurs Brad Dalke (right) and John Oda (center) pose with 2011 U.S. Open champion Rory McIlroy on the 10th hole during Sunday's unofficial practice round at Erin Hills. Dalke was the 2016 U.S. Amateur runner-up. (USGA/Jeff Haynes)

Thomas Pagel, the USGA's senior director, Rules of Golf & amateur status, discusses camera locations at Erin Hills on Sunday with Sam Beim of Fox as the network prepares to broadcast its third U.S. Open. (USGA/Jason E. Miczek)

Stewart Hagestad, the reigning U.S. Mid-Amateur champion, played Erin Hills Sunday with former junior rivals Jordan Spieth and Justin Thomas. (USGA/Jeff Haynes)

Jordan Spieth should have some familiarity with Erin Hills as he advanced to the quarterfinals of the 2011 U.S. Amateur at the Wisconsin layout. (USGA/Jeff Haynes)

Members of the grounds crew work their way down the first hole during Sunday's unofficial practice round. Players are raving about the condition of the 11-year-old layout. (USGA/Darren Carroll)

Two-time U.S. Open champion Ernie Els played Erin Hills on Sunday in preparation for his 25th U.S. Open start. (USGA/Jeff Haynes)

Matt Kuchar, the 1997 U.S. Amateur champion, played Erin Hills on Sunday. (USGA/Jeff Haynes)

Mowers work on the par-4 10th hole on Sunday at Erin Hills. (USGA/Jason E. Miczek)

Looking through the small window of the monster scoreboard on the par-5 18th hole, Hideki Matsuyama, of Japan, plays a bunker shot during Sunday's unofficial practice round. (USGA/Darren Carroll)

Rickie Fowler watches his drive on the seventh hole. Fowler missed the cut in this past week's FedEx St. Jude Classic in Memphis, Tenn., allowing him to get to Erin Hills early to prep for the 117th U.S. Open. (USGA/Jeff Haynes)

A member of the Erin Hills maintenance staff mows the 18th hole during Sunday's unofficial practice round. (USGA/Darren Carroll)