Morganella said he wanted to show that he had learned his lesson while coach Ottmar Hitzfeld said the 23-year-old, included in the squad for a friendly in Greece on Feb 6., had served his punishment and deserved another chance.
"I'm very surprised and happy. I did not expect that," Morganella, who plays for Palermo in Italy's Serie A, told the Swiss Football Federation (SFV) website.
"I want to make sure I justify this decision in sporting terms and show that I have learned from my mistake at the Olympic Games."
Morganella was expelled from the London Games for tweeting a message that the Swiss team said "gravely insulted and violated" the dignity of South Korea following his team's 2-1 defeat by the Asian side.
In part of his message, Morganella said: "I punch you, South Koreans, go burn..."
It was considered by the Swiss team to be sufficiently offensive for the player to be sent home.
"Nobody, neither the SFV nor Swiss Olympic, was in any doubt about how to judge the behaviour of Michel Morganella," said Hitzfeld.
"His comments, especially towards the South Korean people, were strongly condemned, he was immediately excluded from the team and the Olympic games.
"Since then, Michel Morganella has been very insightful in judging his own behaviour. He requested an apology to all relevant parties in a touching and credible letter in August 2012.
"He has acted on his words, has closed his online account and concentrated fully on football. He plays regularly and convincingly for Palermo."
"He was punished and excluded for six months from all activities of the SFV, but now is the time to give him a new opportunity."