Maybe. Or perhaps it is the inverse square root of Koeman saying, "This team is in a lot worse shape than I first thought. What have I let myself in for?"
It's not. At all. It's him telling it how it is. Any manager who is saying his side are 100% match fit and ready for the Premier League season is lying through their teeth. They'll be as ready as they're gonna get without actually playing.
BTW, Spurs (a side whose last PL win came on April 18th and picked up two points from their last available 12) are a lot less prepared than us in terms of game time in pre-season, plus they've flown to Aus and back minus one of their key/best players... I can't imagine their fans will be whinging/heads falling off like this before a ball has even been kicked in anger...