Kieron Dyer is in "intensive training" in a bid to prove his World Cup fitness to England manager Sven-Goran Eriksson by Friday, according to his agent.
It seemed the Newcastle midfielder was ruled out of England's 23-man squad for the finals after a challenge by Southampton defender Tahar El Khalej on Saturday left him with a knee injury.
But Jonathan Barnett insists his client has not given up hope of showing he can be fit when England open their World Cup campaign against Sweden on June 2nd.
He told Sky Sports News: "Kieron is trying his utmost to get fit for the World Cup. He said it's a little bit better than yesterday, he's going to have some intensive training and put his whole heart and soul into it, and if anybody can do it, he can.
"Sven has given Kieron until the end of this week, and I'm sure Kieron will do his utmost to go to the World Cup but he won't if he's not 100 per cent certain he will be fit to play".
Barnett told the Daily Expresshe and Dyer were considering legal redress against El Khalej and Southampton.
"We have considered legal action, certainly against the player and possibly his club," he said. "There is no doubt a player of Kieron's standing would lose out on sponsorship endorsements that might not be realised for another four years".
However, he said it was not something Kieron and he had spoken about.
PA