The DP World Tour has banned players who competed in June’s Saudi Arabian-backed LIV Golf event from next month’s Scottish Open and fined them £100,000.
The players can also not play in the PGA Tour’s Barbasol Championship and Barracuda Championship in July.
The Scottish Open is one of the DP World Tour’s most lucrative events and is used by many players as preparation for The Open, held the following week.
The PGA Tour suspended 17 members who played in the inaugural LIV Golf event.
The DP World Tour, formerly known as the European Tour, has also warned players that “participation in a further conflicting tournament or tournaments without the required release may incur further sanctions”.
Lee Westwood, Ian Poulter, Sergio Garcia, Martin Kaymer and Graeme McDowell are the highest-profile DP World players who will be affected by these initial sanctions.
Players who have joined the LIV Golf series are allowed to play in the 150th Open Championship at St Andrews.
The next LIV Golf tournament in the $250m (£200m) eight-event invitational series is scheduled to take place in Portland, Oregon from 30 June to 2 July.
South Africa’s Charl Schwartzel claimed the first LIV Golf event at Centurion Club in Hertfordshire, winning $4.75m (£3.86m).
The Scottish Open will be co-sanctioned by the DP World Tour and PGA Tour for the first time this year as part of the ‘strategic alliance’ between the circuits.
It returns to The Renaissance Club from 7-10 July and has attracted a high-class field, with Scottie Scheffler, Collin Morikawa, Justin Thomas and Jon Rahm among those signed up to compete for the £6.5m prize fund.
Keith Pelley, DP World Tour chief executive, said: “Every action anyone takes in life comes with a consequence and it is no different in professional sport, especially if a person chooses to break the rules. That is what has occurred here with several of our members.
“Many members I have spoken to in recent weeks expressed the viewpoint that those who have chosen this route have not only disrespected them and our Tour, but also the meritocratic ecosystem of professional golf.
“Their actions are not fair to the majority of our membership and undermine the Tour, which is why we are taking the action we have announced today.”
Four-time major champion Brooks Koepka became the latest player to join LIV Golf earlier this week.
Analysis
BBC golf correspondent Iain Carter
DP World Tour rules precluded the circuit from being able to follow the PGA Tour lead of issuing indefinite suspensions.
Its only option was to ban rebels from the Scottish Open as well as the Barbasol and Barracuda Championships played in the United States next month.
The Wentworth-based organisation’s strategic alliance with the PGA Tour has led to these events being jointly staged by the two tours.
Fines of £100,000 may appear paltry compared with the massive Saudi-funded signing-on fees received by bigger-name LIV recruits, but by golf standards this is a substantial penalty.
There is also the threat of further sanctions for those involved in future LIV events. The next event is in Portland, Oregon, starting on 30 June, the same day as DP World’s Irish Open.
Tour boss Keith Pelley is under pressure from all sides. His sponsors will want big names such as Garcia, Poulter and Westwood at their events while many of his members feel playing opportunities are being squeezed by the strategic alliance.
Unlike PGA Tour commissioner Jay Monahan, Pelley has not subjected himself to questions from the media since the breakaway crisis began. He would be asked about implications for future Ryder Cups, questions to which he currently appears to have no answers.
