It is only then, he believes, that he can start to heal the emotional wounds of the playoff defeat against Crystal Palace last month.
"The disappointment lasts long and that is the one thing about football, unfortunately," he admits.
"Sometimes you have a midweek game and you have the chance to bounce back right away but unfortunately you have a full summer to reflect on a bad result rather than the fantastic performance we were looking for.
"That makes it a little bit more difficult and you have to dust yourself down, but I don't think that will happen until we get back to training."
Peter reveals that he has reviewed the match many times and adds:
"I have seen a video of the game; sometimes, at the time, you paint a worse picture of it than what it was, but the fact remains that we played well below the standard we can.
"People say 'it wasn't as bad as that' but I think differently because I know what the players are capable of.
"It was a disappointing performance - if we had played well and could have said that we didn't get that bit of luck to win any game, you could hang your hat on that a little bit - but there wasn't too much to take out of it, to be perfectly honest."
Peter is in daily contact with Alan Pardew and says:
"Every day we have spoken about it and even on your so-called holiday you are constantly thinking if there is anything you could have done differently.
"You keep scratching your head about it and talk about how positive it has to be for the new season - but you can't really put that into place until you come back in.
"You know what your thoughts are, but you have to put them into practice."
West Ham's pre-season work starts at the beginning of July before a short tour of Sweden.