French side AS Monaco have joined Manchester United in the race to sign Sporting Lisbon midfielder William Carvalho.The talented midfielder has burst on to the scene this season after some consistently impressive performances for Portuguese side Sporting Lisbon, gaining him interest from a number of top European clubs.Premier League side Manchester United have been long-term admirers, whilst a number of Spanish and Italian clubs have also sent scouts over to watch the 21-year-old in action.However, joining interested clubs is French money-men AS Monaco, who, according to LeSport10, are ready to pay his whopping release fee of 37m.Carvalho joined Sporting Lisbon at the age of 13 and has since moved up through the clubs various youth levels.He has represented the Portuguese national side twice and is expected to go to the World Cup this summer in Brazil.Watch Manchester United v Manchester City Tuesday night. 24 hour Sky Sports Day pass for only 9.99. No contract.