Manchester United manager Sir Alex Ferguson has claimed that it is important for David de Gea to improve his strength as soon as possible.
The Spanish youngster has received some criticism during his debut season for United but Ferguson believes that the 21-year-old will benefit from more work in the gym.
The veteran manager said: "The boy has got talent. He's lightning quick but has just found it difficult to adjust to some parts of the game here.
"It's a matter of developing his frame. He's doing a lot of work in the gym.
"If we can get maybe a stone on him without losing any of his flexibility or speed it would be a great boost to him."
De Gea moved to Old Trafford from Atletico Madrid in an £18.3m deal last summer.