The world No 18 has entered the Alfred Dunhill Links Championship in a fortnight’s time, joining fellow American Tony Finau in the star-studded pro-am at Carnoustie, Kingsbarns and St Andrews.
The duo will be bidding to become the first US player to win the tournament, which is celebrating its 20th anniversary this year.
Horschel’s Wentworth win on Sunday saw him become become the first American to claim victory in a Rolex Series event.
European Ryder Cup captain Padraig Harrington is also among the latest players to commit to the Dunhill Links, as have two-time winner Tyrrell Hatton and 2019 Open champion Shane Lowry.
That means three of Europe’s Ryder Cup team at Whistling Straits the previous week are set to play in Scotland, with Tommy Fleetwood already having announced he’d be playing.
Scottish No 1 Bob MacIntyre had done likewise and he’s set to be joined by former winner Stephen Gallacher in flying the Saltire.
Other home players in the field are set to include recent first-time European Tour winners Grant Forrest and Calum Hill, as well as David Drysdale, Scott Jamieson, David Law, Richie Ramsay, Connor Syme and Marc Warren.
Dundee-based Frenchman Victor Perez will be defending the title, having landed his win in 2019 then seeing the 2020 edition cancelled because of the Covid-19 pandemic.
Because of Covid regulations, spectator capacity on each course will be capped at 4,000 on each of the four days and entry will only be permitted to ticket holders.