Other than not wheeling, I got the impression he's not very active normally? If that is the case, some things you can also consider (not necessarily anything that will fix the issue, but throwing them out here in case something pops).... Do you find evidence that he is exploring his cage at night? What is your lighting setup for him? What is the temperature of his cage? How dark is the room he lives in at night?
I ask these as sometimes we find that a temperature issue can cause them to not be as active. Perhaps its good enough to not cause hibernation attempts but still too low. Or it could be too high (depending on where you live).
Lighting can cause issues too. Not enough light during the day, or even too much light during the evening hours. I once had one that stopped running due to a night light that was on at the far end of the house. It didn't light up the room she was in other than casting some light in the hallway.