The 27-year old Guinea-Bissau-born winger has joined the Quakes on loan for the 2014 MLS season pending receipt of his P-1 Visa and international transfer certificate.
The former Sporting Lisbon star brings with him to Buck Shaw Stadium a wealth of experience on Portugal having made over 140 appearances for Sporting as well as 20 while on loan with French club Toulouse last season.
"We're excited to announce the signing of Yannick," said Earthquakes head coach Mark Watson.
"There was a lot of work and time spent scouting in the offseason, and we feel like we have a very good player in Yannick.
"He adds a versatile, attacking dimension to our team. He can operate as an attacking midfielder, but also has the pace to get behind defenders."
Djalo, who has featured just five times for Benfica since joining in 2012, has a Champions League goal with Sporting to his name as well as winning the Portuguese Cup on two occasions, the Portuguese SuperCup twice (with Lisbon) and the Portuguese League Cup once with the Eagles.
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