Barcelona will reportedly only consider selling Manchester United target Jordi Alba if they are forced to by a club triggering the defender's £133 million release clause.

United have been linked with Alba as the left-back edges closer to the final 18 months of his contract in Catalonia, but Sport (h/t TalkSport) reported only by meeting the clause in his agreement will Barca even consider a sale.

Alba has been in hot form of late and scored in Wednesday's 2-0 UEFA Champions League win over Inter Milan before assisting Philippe Coutinho's opener in their 5-1 mauling of Real Madrid in El Clasico on Sunday.

The 29-year-old is one of the best left-backs in the world at his peak, but the chances of United forking out such a monumental figure to reinforce a position that's not of such high priority seem slim.

Alba would become the third-most expensive player of all time if a club did trigger a move, behind only Paris Saint-Germain pair Neymar (£200 million) and Kylian Mbappe (£166 million).

That's not to say Alba isn't an attractive purchase, as the 66-time capped Spain international impressed at the Camp Nou on Sunday and showed his trademark speed down the left to engineer Coutinho's goal:

But United manager Jose Mourinho already has a functional left-back in Luke Shaw, and it would seem ludicrous to purchase a player who would demand to start ahead of the Englishman so soon after he penned an extension.

Shaw signed a new deal until 2023 earlier this month that's worth a reported £190,000 per week, according to the Telegraph's Matt Law.

Considering his initial struggles under Mourinho when he arrived at Old Trafford and then his upturn in form, the resulting extension appeared to suggest the two parties were finally in harmony.

Ex-Premier League midfielder and BBC 5 Live Sport pundit Jermaine Jenas questioned whether the contract extension was Mourinho's decision at all, however:

It makes Alba's arrival so much more difficult to envision, although Squawka's Muhammad Butt lauded the former Valencia star's quality during the absence of an injured Lionel Messi in El Clasico:

Despite Shaw's recent extension, Samuel Luckhurst of the Manchester Evening News recently wrote that Juventus defender Alex Sandro continues to interest the Red Devils as an alternative.

Alba would not settle for such a spot in Mourinho's order and has no reason to leave Barca, where he stands to add more trophies to his collection in light of Real's recent plummet in results this season.