Harry Redknapp believes Tottenham Hotspur playmaker Rafael van der Vaart needs to work on his fitness in order to make an impact for 90 minutes.
Van der Vaart has created an instant impression since joining Spurs from Real Madrid on deadline day and has scored in each of his six appearances at White Hart Lane.
However, Redknapp is concerned that the Holland international is drifting out of the action during the later stages of games.
The former Ajax man has been carrying a slight hamstring strain in recent weeks, but is expected to be fit for Saturday's game against Blackburn Rovers.
Redknapp said: "He should be OK for the weekend. He got tired, didn't he? He disappeared a bit, second half [against Sunderland].
"He's got to get fitter and adapt to playing 90 minutes in the Premier League.
"He's a fantastic player, but I think he does just run out of steam a little bit at the moment."
What will be the outcome in the match Tottenham vs Blackburn?