The striker has failed to impress for club or country this season.
His England hopes are also diminishing, with the likes of Tottenham’s Harry Kane and Leicester City’s Jamie Vardy currently taking the limelight.
There is also Liverpool’s Daniel Sturridge, Arsenal’s Danny Welbeck and Manchester United captain Wayne Rooney filing out the striker roles.
Walcott looks unlikely to be on the plane to France as a result, and Hamann says he will be a big loser this summer.
“Walcott is a big loser, because I think there’s got to be a good chance that he won’t be on the plane to France,” he told talkSPORT.
“I used to be a big fan of his, but the longer I watch him, the more I go off him. He used to rely on his pace as his key strength, and it was often the reason he could find a place in the Three Lions set-up.”
“Now this team is not short of pace. Purely for his pace, that was a big reason for him to go to tournaments, but not anymore.”
England is not the only team Walcott faces a fight to be in, with his Arsenal place also under threat.
Up front, youngster Alex Iwobi has come in and impressed when given the chance, while Olivier Giroud has also do well this season.
The right wing spot is also not his, with Joel Campbell having taken his chance with both hands and arguably ahead of Walcott in the pecking order.