how to keep dog occupied after surgery

So my very very energetic springer spaniel cross had serious surgery last Thursday.
He ate something a Stone or piece of timber that stuck in his bowel.
So thankfully he is doing great now, he thinks he is better!
My problem is now he is not getting stitches out till next Monday, they are right up the middle of his belly.

He is used to long runs up the mountains, on the beach etc. Which obviously he can't do at the moment. He doesn't walk on the lead, he runs everywhere.
I have a head harness thing that stops him pulling so much but the vet thinks it would be bad for him to go 'walking' because of the way he runs and then stops abruptly when the lead extends the full way.

How can I keep him occupied? He is very bored the poor guy and I only have a small back yard so there's not much pottering about for him!

Any suggestions welcome.
Oh and he cannot eat too much yet, on a strict diet, so can't even make him work for treats.

Hooked

Do you own a Kong?

We introduced one when crate training doggie number 2, and bought doggy number 1 one also (then 3 years old)... and were ashamed we hadn't had thought of one for him as a pup.

Depending on the filling, they can really have to work to get food or treats out. And it's limited movement (we give kongs when on crate rest).

tk123

My dog was on crate rest and restricted for 12+ weeks both times. Kongs, chews, treat dispensing toys and practising his training helped use up his energy. I got a book of dog tricks and would teach one a week or even practising basic stuff like sit, stay, touch, leave/take it etc. You could even train him to walk on a loose lead if you put the time in and start inside where there's no distractions.