The ball gets a glance. The tug toy gets ignored. The trick they loved at 6 months gets a look and a wander off, and you feel quietly rejected.
Nothing has gone wrong between you. This is one of the most common things owners describe in the middle of adolescence, and it is usually about the offer rather than the interest.
Check the boring explanations first
Responsiveness to the caregiver's cues drops around the onset of adolescence and returns later in the stage. So the dog least interested in your game at 11 months is often the same dog who was keen at 6 months.
The second explanation is sleep. An under-rested dog looks flat and uninterested, and adds nothing to a game you are working hard to sell.
The third is arousal. Fast repetitive games raise it rather than lower it, so a dog who has had fetch twice a day may be switched on and unable to engage at the same time.
Safety note
Flat is not the same as bored. Book a veterinary appointment if your dog is also eating less, sleeping more than usual, reluctant to move or jump, or has gone quiet over days rather than weeks. Sudden behaviour change warrants a veterinary examination, and pain frequently presents as a change in behaviour rather than as obvious lameness. A dog who has stopped enjoying things they used to enjoy gets checked before they get a new game.
Change what you are offering
An adolescent dog's interests move. The puppy who loved a squeaky toy may now want to use their nose, their teeth or their shoulders instead.
Swap one fetch session for a slow sniffing walk, at whatever pace your dog chooses. Following a nose does calming work that following a ball does not.
Try a scatter feed or a food puzzle instead of a toy. Working for the same meal is a game to most dogs who have gone off toys.
Offer a chew on a mat for 10 to 20 minutes, as a settled activity rather than a burst of speed.
Try one new shape of game: a cardboard box with food in shredded paper, a short trail of treats along the fence, a toy dragged along the ground rather than thrown.
Teach one small new thing rather than repeating a trick they already know. Novelty is often what the old game is missing.
Make sessions shorter than you think
Most owners in this situation are trying harder and longer, which is exactly what makes a dog leave. Stop while your dog still wants more.
Set a timer for 2 minutes and end the session when it goes, even if it is going well.
Run 3 short sessions a day rather than one long one.
Put the toy away between sessions. A toy that lives on the floor all day is furniture.
End with your dog watching the toy go away, rather than with your dog walking off from it.
Pay generously in the first week. You are rebuilding the value of joining in.
Protect the sleep
Give your dog a place to sleep that is out of the traffic, behind a door or a gate if the house is busy.
Build 2 deliberate quiet hours into the day, rather than hoping they happen.
Look at the evening. A dog who cannot come down at 9pm is usually a dog who did not rest at 2pm.
Relaxation is trained as a behaviour in its own right, in short repeatable sets below your dog's threshold. It is not a side effect of a longer walk.
Behaviour change is built from management plus reinforcement together. The management is the sleep and the put-away toys, and the reinforcement is paying for the 2 minutes your dog does join in.
What to expect
Owners usually describe more interest within 2 weeks of shorter sessions and better rest, and a return of enthusiasm through the second year. Some dogs never go back to fetch, and prefer using their nose for the rest of their life.
If the flatness is one of several adolescent things going on at once, the Assessment will name the pattern underneath. It is free, takes about 3 minutes, and asks for no email address.
Today's version, in one line: 2 minutes with the toy, stop while your dog still wants it, then put it away.