Chelsea are due compensation following John Swift’s decision to join Reading.
The 21-year-old free agent, whose contract with Chelsea came to an end this summer, has penned a three-year contract with Royals.
However, the Berkshire outfit will be required to pay a fee for the player as the former Brentford loanee is under the age of 24.
Swift flew out to Holland on Wednesday night to link up with his new teammates, who are on a short European training camp.
He will train for the first time with them on Thursday morning.
Swift is Jaap Stam's fifth signing of the summer after defender Danzell Gravenberch, midfielder Joey van den Berg, striker Joseph Mendes and goalkeeper Anssi Jaakkola.
Manager Jaap Stam said: “John is a very talented player.
“I’ve seen him play and I think he could be very important in the way we want to play.
"He can play as a winger on either side, or as an attacking midfielder. His physique is good, he is good on the ball, he has the pace to get past players, and he has the capability of putting his teammates in front of goal with chances to score.
"He is going to be a big asset for the club."
An England Under-21 international, Swift came through the youth ranks at Stamford Bridge, joining the Blues’ Academy after a successful trial in 2007.
It follows yesterday's depature of Tomas Kalas, with the defender having joined Fulham on a season-long loan deal.