The 28-year old midfielder has been with the Union since January but will head back to the Britannia Stadium at the end of October when the MLS regular season is completed.
Edu has made 29 appearances for Philly, who sit seventh on the Eastern Conference table, but the club is out of play-off contention as they find themselves seven points behind fifth-placed Columbus Crew.
Edu recently suggested that he would be open to returning to Philadelphia if it suited both of the clubs involved.
"These are things that need to be discussed," he said.
"It's out of my hands a little bit. But I've definitely enjoyed it here.
"This is a group I believe in. I have a lot of confidence about things we can achieve."
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