The 16-year-old midfielder decided to join the Gunners despite also being linked with Premier League champions Chelsea.
Feyenoord technical director Leo Beenhakker said: “We did what we could do by offering the kid a contract on time. But he wanted to wait, again this is his right. That he now goes to Arsenal, means that we only get a training allowance.
“This is the story of (Chelsea defender Jeffrey) Bruma, he was also a great talent that unfortunately never played for us. I treasure Ebecilio highly.”
