Andreas Pereira is keen to stay at Manchester United amid interest from Valencia but is set to seek assurances from Jose Mourinho about the opportunities on offer at Old Trafford, sources have told ESPN FC.
Pereira, 21, is wanted by the La Liga side after an impressive campaign on loan at Granada last season.
The midfielder was included in United's squad for the preseason tour of the United States this summer, but he has yet to make an appearance so far this season and did not travel to Swansea for the 4-0 win at the Liberty Stadium on Saturday.
Pereira, who watched the United under-23s' 1-1 draw with Swansea from the stands at Eight Sports Village on Monday night, was also left out of the squad for the UEFA Super Cup defeat to Real Madrid and the opening Premier League game against West Ham.
Having picked the same XI for the first two league games of the season, Mourinho has told his players they will all be needed when campaigns in the Carabao Cup and Champions League kick off after the international break.
The United boss wants to keep Pereira at Old Trafford and sources have told ESPN FC that the Brazil youth international would like to stay, though he is conscious that a year spent on the sidelines could hamper his development following a breakthrough season in Spain.
Valencia, who won their first game of the season against Las Palmas on Friday, have shown the strongest interest, but Mourinho's preference would be for Pereira to secure a loan move within the Premier League if he decides to leave.
Pereira has a year left on his contract with United, holding an option to extend the deal for an additional 12 months. He has made 13 first-team appearances since arriving from PSV Eindhoven in 2011, scoring once.
After returning from Granada this summer he was handed the No. 15 shirt ahead of the new season, having previously worn No. 44.
Valencia general director Mateu Alemany has confirmed his club are monitoring Pereira, as well as Paris Saint-Germain winger Goncalo Guedes.
Asked about his club's interest in the duo, Alemany said during Geoffrey Kondogbia's unveling as a new Valencia player: "I don't like to reveal names or discuss operations but they are two players that interest us. There are others. We shall see."
Superdeporte reports that Valencia have already reached an agreement with PSG for Guedes to join them on a season-long loan, while Valencia owner Peter Lim has travelled to England to meet United executives in order to negotiate Pereira's return to La Liga.
Asked about Lim's involvement in Valencia's negotiations -- the Singaporean businessman, who is on good terms with PSG, also reportedly helped in their pursuit of Guedes -- Alemany said: "Any help is welcome. Peter just happened to be in Paris to watch a game. To use personal relations is good and that can give us a push. We take advantage of everything."
Valencia are looking to strengthen their midfield line after the departure of winger Joao Cancelo, who will join Inter Milan on loan for the 2016-17 campaign.
Cancelo has been included as part of a swap deal that saw midfielder Kondogbia and defender Jeison Murillo arrive at Valencia from Inter.
ESPN FC's Adriana Garcia contributed to this report.