Gabriel, 15, in Barcelona amid speculation over future

Gabriel has not trained at United since scoring a hat-trick on his Uefa Youth League debut on 10 September. Tournament rules prevent him from playing for a side other than United in this season's competition.

Sources close to Gabriel were furious the club did not register him for their Champions League opener with Sabah FK, which Michael Carrick's side won 4-0.

Carrick was again asked about Gabriel on Friday at his news conference to preview Sunday's Premier League match against Fulham.

"He's a young boy, JJ, and I think it's important we don't play anything out here," he said.

"With the exposure and scrutiny and everything, you got to be careful and be sensible and think of him as much as anything.

"The situation will work itself out, whatever way it's going to work itself out. Making sure he's OK is the important thing."

Gabriel scored in his first two Premier League 2 outings for United this season but will not be involved against Brentford at Leigh Sports Village on Friday.