The findings of a FIFA disciplinary committee panel were released by the Canadian Soccer Association, which said the discipline was for "displaying unsporting behaviour towards match officials." Sinclair was also fined an undisclosed amount.
The veteran captain from Burnaby, B.C., had all three goals for Canada that day at Old Trafford. Canada had the lead until the Americans pulled even late in the second half and prevented a big upset by adding the winner in extra time.
The Canadians were left feeling robbed in a loss that they believed was decided by the officials.
"We feel like we didn't lose, we feel like it was taken from us," Sinclair said moments after the final whistle. "It's a shame in a game like that that was so important, the ref decided the result before it started."
The United States would go on to win the gold medal while Canada took the bronze. The CSA said it has contacted FIFA to request the reasons for the judgment and will not comment further until they are received and reviewed.
Peter Montopoli, general secretary of the Canadian Soccer Association said earlier this week that FIFA's disciplinary panel met last Friday. Montopoli, coincidentally, was in Zurich at the time and asked whether he could take part. He was told no representation was allowed, with the explanation that the panel was reviewing many cases and not just Canada's.
Sinclair was the only Canadian player under scrutiny.
The CSA said in a statement Sinclair would speak to media Monday.
The ban is one of the longest in recent Canadian memory.
Fullback Paul Stalteri was suspended for four games after throwing a water bottle off the bench in protest of a nullified goal in a 1-1 World Cup qualifying draw with Honduras in Edmonton in 2004. His red card carried an automatic one-game ban and FIFA added a three-game suspension on top of it.
The Canadian women were upset about a call against goalkeeper Erin McLeod that led to Abby Wambach's game-tying penalty in the 80th minute.
McLeod was whistled for handling the ball for longer than six seconds. The Americans were awarded a free kick inside the box which bounced off the arm of defender Marie-Eve Nault, resulting in the penalty shot.
It's a rule that none of the Canadian players, nor coach John Herdman, nor even American coach Pia Sundhage, had ever seen enforced.
The Canadian women don't have any games scheduled in the immediate future. They are slated to reunite in December for a camp in advance of the Four Nations Cup in China in January. The Cyprus Cup follows that.
Several Canadian athletes immediately took to Twitter on Friday to voice their displeasure about Sinclair's suspension.
"Sinclair suspension is the dumbest thing I have ever heard of!! No guts to do it during the games, what's the point after?," Canadian women's hockey star Hayley Wickenheiser said in a tweet.
Retired freestyle skier Jennifer Heil tweeted that the decision was ''outrageous.'' Sinclair's teammate Emily Zurrer also chimed in.
"Really, FIFA?," she tweeted.
Broadcaster and former men's national team player Jason deVos was also critical of the decision.
"Christine Sinclair fined and suspended four matches by FIFA for 'unsporting behaviour'. Insert joke about FIFA here...," he said.
He added another tweet moments later.
"Imagine if FIFA had made that decision just after the incident had occurred! Yet another black mark for FIFA. #shambles."
Fans were also upset by FIFA's decision.
A Facebook page titled "Christine Sinclair: movement to help pay FIFA's unfair fine" was created within minutes of the announcement and many fans took to Twitter to voice their displeasure with FIFA.
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