The 25-year-old played in 37 league matches for the Swans in 2012-13, bagging five goals, and struck from the penalty spot in the Capital One Cup final win over Bradford.
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“Everyone is happy the loan is continuing,” Swans chairman Huw Jenkins told the club's official website.
“Then Jonathan will review his long-term future next summer.”
De Guzman had recently hinted that he would like to return to Swansea, explaining how much he had enjoyed his original loan spell at the club.
“My ears are always open,” said De Guzman when asked about the possibility of rejoining the Swans. “I had a great year there. The people around the club and the fans treated me well.
“It was not just the results we had, it was more about showing we can also compete with the big teams. We played better against the bigger teams.
“We played well in a lot of games. We played good football and it's refreshing playing in a team that has a good football mind.
“I'm very satisfied with what happened. We did very well - we were very creative. We really put Swansea on the map.”
De Guzman, who is the third signing of the summer for Swansea after Jordi Amat and Jose Canas, scored eight goals and notched a further nine assists in 45 appearances for Swansea in all competitions, earning his first cap for the Netherlands national team in the process.