There are over 150 players in the field.
The second major championship of the year - the US PGA - begins at lunchtime at Oak Hill in New York.
There are four Irish players in the field of 156 - Rory McIlroy, Shane Lowry, Seamus Power and Padraig Harrington.
McIlroy's last major win was in the PGA back in 2014, he's out just after 1pm Irish time.
He will be followed among the early starters by Shane Lowry and Padraig Harrington, with Seamus Power beginning his challenge later on.
The County Down star has spoken about his gameplan as his bids to put his Masters disappointment behind him.
Tuesday Morning Sports Update
Carla Ward Names ROI Women's Squad For FIFA World Cup European Qualifiers
Tottenham Believed To Be In Discussion With Roberto De Zerbi Over Club's Vacant Managers Role
Monday Morning Sports Update
LGFA National League Division 1 - Kildare v Kerry
Hanlon Concrete LTD Senior Football League Results
Kildare U20 Hurling Team vs Westmeath
Hurling League Finals Round-up
