Sergio Busquets has revealed that he will walk away from Barcelona the moment he feels he is unable to do a job for the club.

The long-serving Spanish midfielder has racked up over 500 appearances in a Barca shirt since making his debut in September 2008.

Busquets remains an important part of the team under Ernesto Valverde, being used in 31 of their 34 league matches this term.

Barca have agreed a deal with Ajax for Frenkie de Jong to join in the summer, however, which could potentially reduce Busquets's playing time.

Moving away from Camp Nou is not something that is currently on the 30-year-old's mind, but he is "tempted" to see out his career in Major League Soccer once his powers begin to wane.

"I've always said that I won't be a ​Barcelona player for 20 years with a secondary role," he told Sports Illustrated.

"The moment that I feel my ambition is fading or that I am not able to deliver physically, I will step aside and leave feeling privileged and content of what I gave to the club.

"You can't predict the future, but I am a fan of the United States and soccer over there continues to grow. [​MLS's] competitive style and playoff format is different to what we're used to over here, and that really appeals to me."

Busquets signed a new five-year deal last September that contains a £445m buyout clause.