Garcia withdrew from the DP World Tour's flagship event at Wentworth last month following an opening 76, but did not give tournament officials a reason and was seen in social media posts attending a college football game in Texas two days later.
Players can cite emergency reasons or medical circumstances for withdrawing from events but Garcia failed to provide written evidence of any medical circumstances within the 21-day deadline and has therefore been fined an undisclosed amount.
The BMW PGA Championship is still counted as one of the tournaments Garcia needs to play to remain a DP World Tour member, but the former Masters champion remains one short of the required four this season.
The 42-year-old failed to enter next week's Mallorca Golf Open by Friday's deadline and although he could yet receive an invite to that event or the Nedbank Golf Challenge in November, that appears highly unlikely in the current circumstances.
Only DP World Tour members are eligible for Ryder Cup selection, meaning that the contest's record points scorer could have made his last appearance for Europe against the United States.
Garcia's singles win over Rickie Fowler in 2018 made him the top points scorer in Ryder Cup history with 25.5 and he won three more alongside fellow Spaniard Jon Rahm in the 19-9 defeat at Whistling Straits last year.
Rahm has made it clear he would like to partner Garcia again despite the latter's defection to LIV Golf.
Players who have joined the Saudi-backed breakaway could be banned from the DP World Tour following a legal hearing in February.