The 25-year-old midfielder impressed last season during a loan spell in the Premier League and forced his way into the Holland squad in the process.
"My ears are always open," said De Guzman when asked if rejoining the Swans was a possibility. "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 previously worked under Swansea manager Michael Laudrup at Real Mallorca and added of the Dane: "He knew my situation at Villarreal and he asked if I wanted to join Swansea. It was a no-brainer. I needed a breath of fresh air, and Laudrup gave that to me.
"I got game time and felt part of the team, which was important for me. It was a dream come true."