Sporting Lisbon are bracing themselves for Manchester United and Chelsea to make a bid for William Carvalho in the summer.Despite the Portuguese club insisting they would not consider selling the star they would be powerless to stop him joining the Premier League duo if his 37m release clause is met.The 21-year-old has a contract that runs until 2018 with Sporting even likely to offer him a new deal to fend off interest from European clubs.Carvalho has been linked with Real Madrid along with Man United, who have a good relationship with the Iberian club after signing Cristiano Ronaldo from them in 2003.David Moyes has been searching Europe for a defensive minded midfielder to complement the attacking talent he has at his disposal and is likely to test the waters with an 18m offer, [football] direct news sources have revealed.Chelsea have splashed out on attackers recently but Jose Mourinho wants to add more steel to his midfield.