Vieira was shown a red card midway through the first half of the friendly in Baltimore when referee Baldomero Toledo adjudged the French midfielder to have elbowed Inter defender Marco Materazzi.
Reports have suggested the dismissal could see Vieira banned for the start of the new season, but a spokesman for the FA said: "If a player gets a red card in a friendly he gets a ban for his next friendly, not for competitive matches."
He added: "If it is overseas, it is dependent on it being reported to us by the host FA.
"In general terms, we retain the right to charge players in the most serious of misconduct cases and make sanctions applicable to competitive first-team fixtures if it is felt necessary."
The spokesman indicated the incident involving Vieira was not viewed as being such a case.
Rafael Benitez's Inter side ran out comfortable 3-0 winners after Vieira departed the field, with Victor Obinna opening the scoring via a deflection off Micah Richards, an own goal from Joleon Lescott doubling the Nerazzurri's lead and Cristiano Biraghi sealing matters.
City assistant manager Brian Kidd felt the decision to send Vieira off was harsh.
"Patrick has gone for the ball," Kidd said.
"He genuinely didn't see the player. There was no intent there. Hopefully people will realise that it wasn't a genuine foul."
Source: PA
Source: PA