Barcelona's Alexis Sanchez (L) fights for the ball against Valencia's Juan Bernat during their Spanish first division soccer match at Camp Nou stadium in Barcelona February 1, 2014.
Juan BernatReuters

Valencia have reportedly started their search for a left-back as they contemplate life without starlet Juan Bernat as a number of big European clubs including Chelsea and Manchester United consider a summer bid.

The 21-year-old full back is proving to be a sensation in La Liga this season after abandoning his original role as a winger for a deeper position at left back.

And Spanish newspaper Marca reports that despite Bernat being a pivotal player for Valencia this season the Spanish side will not block his exit in the summer should the right offer come in.

Valencia still face economic concerns and in recent years have been faced with no other option but to cash in on their most prized assets such as Juan Mata, David Silva, David Villa and Jordi Alba.

And according to Marca, Bernat maybe the next one to leave the Spanish strugglers at the end of the season. In an added problem, the defender's contract at the Mestalla Stadium expires in 2015, leaving the club to decide whether to sell and recoup a transfer fee this summer or risk losing him for nothing next year.

Bernat's release clause is understood to be around £20m but according to reports in Spain Valencia may sanction a deal for just £8m, with reports claiming that both United and Chelsea are monitoring the situation.

With Patrice Evra set to leave Old Trafford at the end of the season once his contract at United expires, David Moyes is desperately looking for a replacement and Valencia-based newspaper Super Deporte recently claimed that United scouts were in attendance watching Bernat at the Mestalla during his side's 1-1 draw against Athletic Bilbao.

Meanwhile, Jose Mourinho is also reportedly interested in his services. Ashley Cole's contract at the club is also due to expire in the summer and having been displaced as first-choice left-back by Cesar Azpilicueta this season, his future at Stamford Bridge looks uncertain.