The 30-year old attacker has been training with the Quakes since January and earlier this week put pen to a deal, delighting general manager John Doyle.
"Eduardo will bring a lot to our club," Doyle said.
"He is a physical presence up top with the ability to hold the ball, and he also has great feet. He has proven that he can score goals in quality leagues around the world and we think that he will have success in MLS also."
He enjoyed a loan spell with Basel in 2005 before signing permanently where he scored 17 goals in 96 games and helped it win the Swiss league championship in 2005 and 2008 and Swiss Cup titles in 2007 and 2008 prior to the club releasing him last June.