Although Wayne Rooney's position in the tour party does not appear to be at risk, a number of his teammates could miss out on the trip to Brazil.
However, the likes of Danny Welbeck, Michael Carrick, Chris Smalling, Phil Jones, Ashley Young and Tom Cleverley are United players who are far from certain of making the plane to Brazil.
And Hodgson admits that United's poor season is a clear indication that their form has not been food.
Hodgson pointed out: "Manchester United are one of the few teams that have had a lot of English players but football players have to accept their England careers are tied up with their club careers.
"If it's not going well in their clubs, and it's not going well for them, it does put your position as a national team player under some sort of threat.
"It is the worst part of the job. It's a major downside that I can only take 23."
Which United stars would you take to Brazil? Don't forget you can put yourself in Hodgson's shoes with Sky Sports' England Squad Selector. Click here to make your choices.
@tk421 - you're so right mate. With 8 goals in his last 8 PL games, Rooney must be way down the list of English strikers in the form stakes. Just remind of the names of those strikers who are more 'in form' though - my memory lets me down at times.- big dave