Nani set for exit after walking out

Half-time substitution may be last straw as United's winger leaves ground early

(GETTY IMAGES)

The Manchester United future of Nani, the Portuguese signed to take over Ryan Giggs' mantle, is in increasing doubt after he left Old Trafford before the end of Saturday's game, having been substituted at half time.

The 22-year-old is understood to have been "very upset" after Sir Alex Ferguson did not send him out for the second half against Tottenham and he left the stadium around 10 minutes before the end, having watched his replacement, Carlos Tevez, help inspire United's comeback. He will not be fined and his unwillingness to stay around to see his jubilant team-mates is not strictly against club rules but it raises serious doubts about his future.

Sources close to the player in Portugal suggested yesterday that if Cristiano Ronaldo, his main ally at United, leaves for Real Madrid this summer then Nani will depart too – probably for Internazionale. The player said last night: "I was not satisfied about my role against Tottenham but I accept the orders of the coach by the substitution at half-time. The team changed in many ways during the second half but I wasn't responsible for the first 45 minutes. I finished the match unhappy though I am still waiting to demonstrate what I can do."

But his early removal on Saturday looked justified and continues a dire season in which the left midfielder, signed for £14m from Sporting Lisbon, has been substituted on each of his six league starts and never made it beyond 70 minutes. Nani insisted he wanted to stay and fight for his United future. "I have signed a deal with this club and my dream is to obtain a permanent place in the eleven," he said.

But Ferguson's decision to buy the Partizan Belgrade winger Zoran Tosic in January raised questions, even though the Serbian has not developed physically in time to feature this season as Ferguson had hoped. If United move for Wigan's Antonio Valencia in the close season Nani would appear to have little prospect of staying.

Nani said in an interview with Portuguese journalists a few months back that he did not understand why he had such a bad press in England this season because although he is playing less, he has scored more – six goals compared to four last season. There was widespread surprise when United paid out such a sum for him in the summer of 2007, although his United career started promisingly. He scored a spectacular 30-yard winner against Spurs at the start of last season before setting up the goals which enabled United to shade 1-0 wins against Sunderland and Everton and scoring against Liverpool.

Nani, who grew up in a tough district of Lisbon, has always been a difficult character. Even when he was winning plaudits at Sporting, he lacked Ronaldo's charisma and his decline can be tracked to his unfathomable headbutt on the West Ham defender Lucas Neill in the penultimate league game of last season.

The Brazilian right-back Rafael, whose torrid time against Luka Modric on Saturday was out of keeping with a fine first season at United, has been given a two-year contract extension which will keep him at Old Trafford until June 2013. His twin brother Fabio has not played enough games for United to have warranted a contract extension, though his initial deal takes him through to 2011 at least.

"Everyone at the club has been very impressed and excited by [Rafael's] first year as a professional," Ferguson said. "His enthusiasm and the adventurous way he plays is typical of a Manchester United player and we are delighted that he has signed a new contract."