Your kid does not want to go to practice. They said their stomach hurts. They came home from the game in a bad mood and did not want to talk about it. You are trying to figure out whether this is a rough patch or something that actually needs your attention.
The honest answer is that you cannot tell from a single day. The difference between burnout and a bad week is almost entirely about duration and pattern.
A bad week has a visible cause. A hard loss. A conflict with a teammate. A coach who said something that landed wrong. A Thursday where three things went sideways at once. The mood is off, but if you watch closely, you will see your kid still light up around the parts of the sport they love. They still mention a friend from the team at dinner. They still pick up the ball in the backyard.
Burnout does not have a single cause you can point to. It builds across weeks, sometimes months, and by the time you notice it you are usually looking at it in the rearview mirror. The signs are consistent rather than one-off: avoidance at practice most days, not just some. Mood changes that persist at home, not just after games. A kid who cannot name anything good about the sport when you ask.
The response to a bad week is patience and space. The response to burnout is structural change. If you treat burnout like a bad week, it gets worse. If you treat a bad week like burnout, you create a problem that was not there before by over-responding to normal stress.
The most useful thing you can do right now is track the pattern over two to three weeks, not just today. Are the avoidance signals consistent, or do they come and go? Does your kid have any stretches where they seem engaged and willing? Has there been any real recovery time in the past month? A week fully off, a weekend with nothing sport-related?
The clearest single signal of burnout, as opposed to a rough patch, is that rest does not help. A kid having a bad week usually rebounds with a day off, a good meal, decent sleep, and some distance from the last bad game. A kid in burnout territory does not rebound much, even with rest. The tank does not refill the way it used to.
If you are still not sure, that is actually useful information. It means the pattern is not clear enough yet to diagnose. Watch two more weeks before you act. If the score is low in two weeks, you have your answer. If it has climbed, now you are dealing with something real and you act accordingly.
The one thing that does not help in either situation is pushing harder. That is the instinct, and it is almost always wrong.