PITTSFORD, N.Y. (AP) — The PGA Championship is officially underway at Oak Hill.

Shaun Micheel, the 2003 PGA champion, kicked off golf's second major of the year with the opening tee shot following a frost delay of nearly two hours.

The delay likely means the groups in the 156-player field teeing off later in the day may have trouble finishing their rounds on the East Course before darkness.

Defending champion Justin Thomas begins his bid for a third PGA championship a little after 10 a.m. EDT. Thomas is playing with two-time PGA champion Rory McIlroy and 2020 PGA champion Collin Morikawa.

Masters champion and No. 1 Jon Rahm is playing with British Open champion Cameron Smith and U.S. Open champion Matt Fitzpatrick. Scottie Scheffler, the world's second-ranked player, is in a group that includes two-time PGA champion Brooks Koepka.

Thick rough and chilly temps in the morning will make the par-70 layout even more difficult for the early starters. Temperatures are expected to rise throughout the day, topping out in the mid-60s in the afternoon.

___

This is what everyone feared about Oak Hill hosting the PGA Championship in May.

Baby, it's cold.

The opening round is being delayed by frost and everyone is being ordered to stay off the lawns. Fairways were covered by a thin layer of frost. Temperatures were right around freezing as dawn broke.

The good news for the PGA Championship is it won't last long. The PGA of America said the first tee time would be 1 hour, 15 minutes after the practice facilities are open. And the weather is expected to get warmer each day the rest of the week.

Shaun Micheel is to hit the opening tee shot, an honor afforded the oldest former champion in the field. He won the PGA at Oak Hill in 2003. That was his only PGA Tour win.

___

AP golf: https://apnews.com/hub/golf and https://twitter.com/AP_Sports