LOS ANGELES -- Manchester United have confirmed that Daley Blind has left to join Ajax on a four-year contract.

Sources told ESPN FC the fee for the 28-year-old is £14.1 million, possibly rising to £18.5m with add-ons, giving United a slight profit on the £13.8m they paid Ajax for his services in 2014.

A statement issued by United on Monday read: "We have agreed terms with Ajax for the transfer of Daley Blind. A further announcement will be made in due course."

In a tweet confirming the sale on Tuesday, United added: "Thanks for everything, Daley, all the best for the future."

I want to thank you for all the love and support I received and still get. I will never forget some of the special games and moments, I will miss you 'The Theatre of Dreams'! But now its time to go home. 🔴 #MUFC (3/3) pic.twitter.com/GScz9Z6teb — Daley Blind (@BlindDaley) July 17, 2018

Blind said farewell to United in three posts made from his Twitter account.

"First of all I want to say how proud I am to be a part of the Manchester United family," he wrote. "To play for the biggest club in the world with such a history meant a lot to me. I had 4 great years with 4 trophy's [trophies]!

"I want to thank everyone, the Managers, coaches, the medical department, everyone who helped me to settle in so quick at the beginning, of course my teammates and last but definitely not least the fans!

"I want to thank you for all the love and support I received and still get. I will never forget some of the special games and moments, I will miss you 'The Theatre of Dreams'! But now its time to go home."

The deal has been expected for some time, and the Netherlands international was not part of the United squad that flew to Los Angeles for their preseason tour on Sunday night.

Blind met up with the Ajax squad at their training base at St George's Park on Monday, sources said. The Dutch side are due to play in England next week against Wolves and Walsall.

At United, Blind was a regular under former boss Louis van Gaal but struggled to establish himself Jose Mourinho and was restricted to just four Premier League starts last season.

In four years at Old Trafford, Blind made 141 appearances in all competitions, scoring six times.