The USA's Laguna Seca Grand Prix has been dropped from the provisional 2014 MotoGP calendar.
Laguna Seca has hosted a race every year since 2005 but its place on the calendar was put into doubt by the addition of the Grand Prix in Austin.
The British Grand Prix will take place at Silverstone on 31 August.
The United States will host two races - the Grand Prix of the Americas, in Austin, and the Indianapolis Grand Prix.
A statement from the Laguna circuit said: "Unfortunately, and in spite of loyal support from fans, sponsors and media, there will not be a 16th US Grand Prix in 2014.
"At this time, the US is only able to support two MotoGP events.
"The support provided by the states of Texas and Indiana make it difficult for us, as a not-for-profit, to currently compete."
The Brazilian Grand Prix, if it is confirmed, will be held on 28 September. The race is subject to the track being approved as it needs to be renovated, with work scheduled to start in December and finish in April or May.
Brazil last hosted a Grand Prix in 2004, when the Rio Grand Prix was won by Makoto Tamada.
The Termas de Rio Hondo hosts the third race of the season, to be held on 27 April. It sees MotoGP return to Argentina for the first time since 1999, when the 500cc race at the Autodromo Oscar A Galvez in Buenos Aires was won by American Kenny Roberts Jr.
The British round keeps its slot at the end of August, after moving there from its regular June date this year.
Provisional 2014 MotoGP calendar
23 March: Qatar (Doha/Losail) - evening race
13 April: Americas (Austin)
27 April: Argentina (Termas de Rio Hondo)
04 May: Spain (Jerez de la Frontera) - subject to contract
18 May: France (Le Mans)
1 June: Italy (Mugello)
15 June: Catalunya (Barcelona-Catalunya)
28 June: Netherlands (Assen) - Saturday race
13 July: Germany (Sachsenring)
10 August: Indianapolis GP (Indianapolis)
17 August: Czech Republic (Brno)
31 August: Great Britain (Silverstone)
14 September: San Marino & Riviera di Rimini (Marco Simoncelli Misano)
21 September: Aragon (MotorLand Aragon)
28 September: Brazil (Brasilia) - subject to approval
12 October: Malaysia (Sepang)
19 October: Japan (Motegi)
26 October: Australia (Phillip Island)
09 November: Valencia (Ricardo Tormo-Valencia)